Multifunctional and sustainable nanomaterials

[OPEN POSITION]: PhD student in Neutron scattering - Probing multiple length scales in functional nanomaterials

2018-10-11T13:36:00.000+02:00

at the Department of Materials and Environmental Chemistry. Closing date: 5 November 2018.

The Department of Materials and Environmental Chemistry (MMK) is one of the largest departments at the Faculty of Natural sciences with about 130 employees. The research activities of MMK are in the areas of Materials and Solid-state Chemistry focusing on different classes of materials; e.g. ceramics and glasses, self-assembled and porous materials, and soft matter. The work often encompasses synthesis, characterisation by X-ray diffraction and electron microscopy, NMR studies, modelling with computer simulations of materials with a potential for various applications. Environmental aspects are an important part of the research activities.

Project description Project title: Neutron scattering as a multiple length scale probe for functional nanomaterials.

Supervisor: Associate Prof. German Salazar Alvarez, german.salazar.alvarez@mmk.su.se.

The project will focus on studying different types of nanomaterials with neutron scattering at the atomic (diffraction) and nanoscopic (small angle neutron scattering, SANS) levels. The work implies comprehensive experiments with neutron scattering in neutron facilities around the world with focus on the multiple length scale approach. The work also includes development, and testing of different sample environments for in-situ characterisation of nanomaterials.

The project is a collaboration between Stockholm University (SU), Uppsala University (UU), and the European Spallation Source (ESS) and has as a long-term plan to expand the neutron diffractometer DREAM at the ESS in Lund to study nanomaterials. Within the project, we will design different sample environments to enable the simultaneous acquisition of data in two length scales (atomic and nanoscopic). In this way, the connection between the variations in the crystal structure and nanoparticle morphology can be established. This will be used to study three different materials classes that have a strong research tradition in Sweden: biomaterials, batteries, and magnetic materials. Some examples of the possible studies include self-assembly of small cellulose fibres, how the structure of batteries changes during usage, or how magnetic nanoparticles assemble under an applied magnetic field. The project is financed by the Swedish Research Council.

The successful candidate should have a background in chemistry or materials science with an interest in utilizing characterization methods such diffraction with Rietveld analysis and/or small-angle scattering. Experience in PDF-analysis of nanomaterials is advantageous. Knowledge of TEM is meritorious but not a requirement.

Qualification requirementsIn order to meet the general entry requirements, the applicant must have completed a second-cycle degree, completed courses equivalent to at least 240 higher education credits, of which 60 credits must be in the second cycle, or have otherwise acquired equivalent knowledge in Sweden or elsewhere.

In order to meet the specific entry requirements, the general syllabus for doctoral studies in the field of Materials chemistry is valid. Those studies should include at least one specialized course or a thesis in the research subject. In order to facilitate the evaluation of merits and suitability for the PhD studies your curriculum vitae (CV) should contain information about the extent and focus of the academic studies. The quantity (as part of an academic year) and the quality mark of courses in chemistry and physics are of particular interest. Please, state titles of undergraduate theses and project works.

The primary assessment criteria in appointing a doctoral student should be the capacity to benefit from the training. The qualification requirements must be met by the deadline for applications.

SelectionThe selection among the eligible candidates will be based on their capacity to benefit from the training. A committee will go through the applications and rank after the applicants capacity to benefit from a PhD education. The following criteria will be used to assess this capacity: the candidates’ documented knowledge in a relevant field of research, written and oral proficiency in English, the capacity for analytical thinking, the ability to collaborate, as well as creativity, initiative, and independence. The assessment will be based on previous experience and grades, the quality of the degree project, references, relevant experience, interviews, and the candidate’s written motivation for seeking the position. A short list will be set up and interviews with the top candidates will be carried out at the department or via internet.

Economic support for the PhD studies are guaranteed for full time studies during the time period agreed on in the individual study plan. The studies does normally mean four years full time studies. You are encouraged to contact the project leader for more information about the project. For general information about the Department of Materials and Environmental Chemistry please contact the Head of the Department, Professor Gunnar Svensson, gunnar.svensson@mmk.su.se.

Admission Regulations for Doctoral Studies at Stockholm University are available at: www.su.se/rules.

Terms of employment Only a person who will be or has already been admitted to a third-cycle programme may be appointed to a doctoral studentship.

The term of the initial contract may not exceed one year. The employment may be extended for a maximum of two years at a time. However, the total period of employment may not exceed the equivalent of four years of full-time study.

Doctoral students should primarily devote themselves to their own education, but may engage in teaching, research, and administration corresponding to a maximum of 20 % of a full-time position.

Please note that admission decisions cannot be appealed.

Stockholm University strives to be a workplace free from discrimination and with equal opportunities for all.

Contact
For more information, please contact Associate Prof. German Salazar Alvarez, telephone: +46 8 16 39 42, german.salazar.alvarez@mmk.su.se.

Union representatives
Ingrid Lander (Saco-S), telephone: +46 708 16 26 64, saco@saco.su.se, Lisbeth Häggberg (Fackförbundet ST and Lärarförbundet), telephone: +46 8 16 20 00 (operator), seko@seko.su.se(SEKO), and PhD student representative, doktorandombud@sus.su.se.

Application
Apply for the PhD student position at Stockholm University's recruitment system. It is the responsibility of the applicant to ensure that the application is complete in accordance with the instructions in the advertisement, and that it is submitted before the deadline.

Please include the following information with your application

Your contact details and personal data
Your highest degree
Your language skills
Contact details for 2–3 references

and, in addition, please include the following documents

Cover letter
CV – degrees and other completed courses, work experience and a list of degree projects/theses
Project proposal/Research proposal describing:
– why you are interested in the field/project described in the advertisement
– why and how you wish to complete the project
– what makes you suitable for the project in question
Degree certificates and grades confirming that you meet the general and specific entry requirements (no more than 6 files)
Letters of recommendation (no more than 6 files)
Degree projects/theses (no more than 6 files).

The instructions for applicants are available at: Instructions – Applicants.

You are welcome to apply!

Stockholm University – our education and research produce results.

URL to this pagehttps://www.su.se/english/about/working-at-su/phd?rmpage=job&rmjob=7028&rmlang=UK

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[OPEN POSITION]: PhD student in Materials Chemistry

2018-03-09T15:10:00.000+01:00

PhD student in Materials Chemistry

at the Department of Materials and Environmental Chemistry. Closing date: 24 April 2018.

The Department of Materials- and Environmental Chemistry (MMK) is one of the largest departments at the Faculty of Natural sciences with about 130 employees. The research activities of MMK are in the areas of Materials and Solid-state Chemistry focusing on different classes of materials; e.g. ceramics and glasses, self-assembled and porous materials, and soft matter. The work often encompasses synthesis, characterisation by X-ray diffraction and electron microscopy, NMR studies, modelling with computer simulations of materials with a potential for various applications. Environmental aspects are an important part of the research activities.

Project descriptionProject title: In-situ characterization of nanoparticles for electrocatalytic production of hydrogen.

Supervisor: Associate Prof. Germán Salazar-Alvarez, german.salazar.alvarez@mmk.su.se.

This PhD project will focus on the synthesis of catalytic nanomaterials for the partial oxidation of alcohols and their operando characterization using total scattering at synchrotron facilities and in-situ IR spectroscopy.

The target of the program is to develop efficient and selective catalysts through an effort involving theory, materials and electrocatalytic design and testing. The approach in the present project is in particular to fabricate and characterize nanomaterials to partially oxidize excess glycerol from biofuel production and waste carbohydrates from wood-based Kraft pulp processes to produce valuable chemicals and hydrogen. This PhD project is part of the program Materials for energy applications funded by the Swedish Foundation for Strategic Research (SSF). The project will be carried out in close collaboration within the project consortium consisting of researchers from KTH and SU and a couple of Swedish enterprises. A considerable part of the experiments will be carried out at synchrotron facilities around the world, primarily in Hamburg.

The successful candidate should have a background in chemistry or materials science with an interest in nanoparticle synthesis and in utilizing characterization methods such X-ray diffraction with Rietveld analysis. Experience in PDF analysis of nanomaterials and other related synchrotron techniques is advantageous. Knowledge of IR spectroscopy and TEM is meritorious but not a requirement.

More details on requirements and how to apply at

https://www.su.se/english/about/working-at-su/phd?rmpage=job&rmjob=5052&rmlang=UK

[OPEN POSITION]: PhD student in Inorganic Chemistry

2018-03-09T15:04:00.006+01:00

at the Department of Materials and Environmental Chemistry. Closing date: 24 April 2018.

Project descriptionProject title: Synthesis and characterization of nanoparticles for electrocatalytic production of hydrogen.

Supervisor: Professor Mats Johnsson, mats.johnsson@mmk.su.se.

The project will focus on synthesis and characterization of nanoparticles aimed as electrocatalysts for hydrogen production based on excess glycerol from biofuel production and waste carbohydrates from wood-based Kraft pulp processes.

Many research projects aiming at hydrogen production focus on water splitting. The water oxidation reaction is associated with high anodic potentials due to unfavorable thermodynamics and slow reaction kinetics. Oxygen is a by-product from hydrogen production from water and is normally just released into the atmosphere. The approach in the present project is to replace the anodic reaction with partial oxidation of alcohols that results in a large decrease in electrical energy demand for hydrogen evolution and also valuable anodic products. This PhD project is part of the program Materials for energy applications funded by the foundation for strategic research (SSF). The project group consists of researchers from KTH and SU and the PhD student will also interact with Swedish enterprises. The target of the program is development of efficient and selective catalysts through an effort involving theory, materials and electrocatalytic design and testing.

The successful candidate should have a background in chemistry or materials science with an interest in synthetic inorganic chemistry and in utilizing several characterization methods such as SEM-EDS, TEM, Powder X-ray diffraction, and electrochemical measurements. Knowledge of those methods is a plus although not strictly required.

More info on requirements and how to apply at:

https://www.su.se/english/about/working-at-su/phd?rmpage=job&rmjob=4999&rmlang=UK

[Project grant] SSF: Electrolysis for hydrogen as energy carrier

2018-02-07T14:02:00.000+01:00

A team led by Ann Cornell, professor at the Department of Applied Electrochemistry, KTH, has been awarded 27,6 MSEK by the Swedish Foundation for Strategic Research SSF, to develop "Electrolysis for hydrogen as energy carrier". Congratulations!

Co-applicants:

- Gunnar Henriksson, KTH
- Mats Johnsson, SU
- Lars Petterson, SU
- German Salazar-Alvarez, SU

Contact:

Ann Cornell

(amco@kth.se)

Mer info på svenska här:
https://strategiska.se/pressmeddelande/deras-nya-material-ska-ge-effektivare-energisystem/

Experimental investigation of the flow and heat transfer of magnetic nanofluid in a vertical tube in the presence of magnetic quadrupole field

2017-11-02T13:45:00.000+01:00

Sajjad Ahangar Zonouzi, Rahmatollah Khodabandeh, Habibollah Safarzadeh, HabibAminfar, Yuliya Trushkina, Mousa Mohammadpourfard, Morteza Ghanbarpour, German Salazar-Alvarez

Experimental Thermal and Fluid Science (2017) In press
DOI: 10.1016/j.expthermflusci.2017.10.013

Abstract:
In this paper, the effects of applying magnetic field on hydrodynamics and heat transfer of Fe3O4/water magnetic nanofluid flowing inside a vertical tube have been studied experimentally. The applied magnetic field was resulted from quadrupole magnets located at different axial positions along the tube length. The variations of the local heat transfer coefficient and also the pressure drop of the ferrofluid flow along the length of the tube by applying the magnetic quadrupole field have been investigated for different Reynolds numbers. The obtained experimental results show maximum enhancements of 23.4%, 37.9% and 48.9% in the local heat transfer coefficient for the magnetic nanofluid with 2 vol.% Fe3O4 in the presence of the quadrupole magnets located at three different axial installation positions for the Reynold number of 580 and the relative increase in total pressure drop by applying the magnetic field is about 1% for Re=580. The increase of the heat transfer coefficient is due to the radial magnetic force toward the heated wall generated by magnetic quadrupole field acting over the ferrofluid flowing inside the tube so that the velocity of the ferrofluid in the vicinity of the heated wall is increased. It is also observed that the enhancement of heat transfer coefficient by applying magnetic quadrupole is decreased with increasing the Reynolds number.

[MRS Symposium] SM07 - Functional (Bio)polymers in Energy and Environment Applications

2017-10-13T12:01:00.005+02:00

Time and time again, "multidisciplinary" research is touted as essential to innovation. That is why, from April 2-6, 2018, researchers working in seemingly unrelated fields will gather in Phoenix, Arizona, to promote, share and discuss issues and developments across disciplines.

The 2018 MRS Spring Meeting & Exhibit is the key forum to present research to an interdisciplinary and international audience. It provides a window on the future of materials science, and offers an opportunity for researchers—from students and postdoctoral fellows, to Nobel and Kavli Prize Laureates—to exchange technical information and network with colleagues.

Call for Papers

Submit an Abstract

Abstract submission deadline is October 31, 2017.

Symposium SM07—Functional (Bio)polymers in Energy and Environment Applications

The development of inexpensive, benign and efficient sustainable materials, which can replace our dependence on the fossil reserves, is imperative. This approach can take many forms, either by improving the lifetime of a material, making it lighter, easier and more economical to transport, or by creating novel materials that allow for new functions. In this context, the exploitation of functional materials based on renewable and sustainable (bio)polymers and bioplastics (i.e., biological polymers and bio-derived synthetic polymers) such as poly(ionic liquid)s (PILs), polysaccharides, fibrous proteins, etc represents an approach that can satisfy these stringent requirements.

Improved chemical and characterization methods have promoted the growing interest in (biopolymers as it enabled tuning their surface properties and the observation of their intricate nanostructures. Functional biopolymers and bioplastics have found their way in applications in catalysis, sensing, energy storage and energy generation. However, the understanding of the coupling of the micro-, meso-, and macroscopic-length scales is far from being understood, particularly in combination with inorganic nanomaterials. This symposium will cover the range of applications of biopolymers and bioplastics in energy and environment applications.

The topics of the symposium include interdisciplinary areas merging chemistry, biology, polymer science and materials science. The invited abstracts will provide the required bridges to connect these areas with an emphasis on their characterization methods and applications. These, in turn, will help to initiate discussions towards the implementation of the various functional (bio)polymers in different areas and the cross-fertilization of the characterization methods that are used.

Topics will include:

Thermal insulation
Ionic and electronic conductors
Environmental remediation (heavy metal sorption, organic dye removal, etc.)
Life-cycle analysis
Sensing
Catalysis
Energy generation and storage (supercapacitors, battery, triboelectricity, piezoelectricity, biofuel cells, etc)
Advanced characterization of (bio)polymers
Functionalization of biopolymers
Functional carbons from (bio)polymers

Invited Speakers:

Laurent Billon (Université de Pau et des Pays de l'Adour, France)
Niklas Hedin (Stockholm University, Sweden)
Olli Ikkala (Aalto University, Finland)
Timothy Long (Virginia Polytechnic Institute and State University, USA)
Isabel Marucho (Universidade Nova de Lisboa, Portugal)
Hideharu Mori (Yamagata University, Japan)
Meital Reches (Hebrew University of Jerusalem, Israel)
Daniel Taton (Université de Bordeaux and CNRS, France)
John Texter (Eastern Michigan University, USA)
Magdalena Titirici (Queen Mary University of London, England)
Silvia Vignoli (University of Cambridge, England)
Feng Yan (Soochow University, China)

Symposium Organizers

German Salazar-Alvarez

Stockholm University

Materials and Environmental Chemistry

Sweden

+468163942, german@mmk.su.se

Marie-Helene Delville

Institut de Chimie de la Matière Condensée de Bordeaux

Chemistry of Nanomaterials

France

+33-5-40-00-84-60, Marie-helene.DELVILLE@icmcb.cnrs.fr

Bernd Wicklein

Materials Science Institute of Madrid-CSIC

Spain

34-91-3349000, bernd@icmm.csic.es

Jiayin Yuan

Clarkson University

Department of Chemistry and Biomolecular Science and Center for Advanced Materials Processing

USA

315-268-4247, jyuan@clarkson.edu

Keywords for Abstract Submission

characterization of biopolymers, Energy generation and storage, Environmental remediation, functionalization of biopolymers, Ionic and electronic conductors, sensing and catalysis, Thermal insulation

Effects of Different Manufacturing Processes on TEMPO-oxidized CNF Performance as binder for Flexible Lithium-ion Batteries

2017-10-09T12:37:00.000+02:00

Huiran Lu, Valentina Guccini, Hyeyun Kim, German Salazar-Alvarez, Göran Lindbergh, and Ann Cornell*

ACS Appl. Mater. Interfaces (2017)
DOI: 10.1021/acsami.7b10307

Abstract:
Carboxylated cellulose nanofibers (CNF) prepared using the TEMPO-route are good binders of electrode components in flexible lithium-ion batteries (LIB). However, the different parameters employed for the defibrillation of CNF, such as charge density and degree of homogenization, affect its properties when used as binder. This work presents a systematic study of CNF prepared with different surface charge densities and various degrees of homogenization and their performance as binder for flexible LiFePO4 electrodes. The results show that the CNF with high charge density had shorter fiber lengths compared with the CNF with low charge density, as observed with atomic force microscope (AFM). Also, CNF processed with a large number of passes in the homogenizer showed a better fiber dispersibility, as observed with rheological measurements. The electrodes fabricated with highly charged CNF exhibited the best mechanical and electrochemical properties. The CNF at the highest charge density (1550 µmol g-1) and lowest degree of homogenization (3+3 passes in the homogenizer) achieved the overall best performance, including a high Young’s modulus of approximately 311 MPa and a good rate capability with a stable specific capacity of 116 mAh g-1 even up to 1C. This work allows a better understanding of the influence of the processing parameters of CNF on their performance as binder for flexible electrodes. The results can also contribute to the understanding of the optimal processing parameters of CNF to fabricate other materials, e.g., membranes or separators.

[OPEN ACCESS] Superlattice growth and rearrangement during evaporation-induced nanoparticle self-assembly

2017-07-18T15:58:00.003+02:00

Elisabeth Josten*, Erik Wetterskog, Artur Glavic, Peter Boesecke, Artem Feoktystov, Elke Brauweiler-Reuters, Ulrich Rücker, German Salazar-Alvarez, Thomas Brückel & Lennart Bergström

Scientific Reports 7 (2017) 2802
DOI: 10.1038/s41598-017-02121-4

Abstract:
Understanding the assembly of nanoparticles into superlattices with well-defined morphology and structure is technologically important but challenging as it requires novel combinations of in-situ methods with suitable spatial and temporal resolution. In this study, we have followed evaporation-induced assembly during drop casting of superparamagnetic, oleate-capped γ-Fe2O3 nanospheres dispersed in toluene in real time with Grazing Incidence Small Angle X-ray Scattering (GISAXS) in combination with droplet height measurements and direct observation of the dispersion. The scattering data was evaluated with a novel method that yielded time-dependent information of the relative ratio of ordered (coherent) and disordered particles (incoherent scattering intensities), superlattice tilt angles, lattice constants, and lattice constant distributions. We find that the onset of superlattice growth in the drying drop is associated with the movement of a drying front across the surface of the droplet. We couple the rapid formation of large, highly ordered superlattices to the capillary-induced fluid flow. Further evaporation of interstitital solvent results in a slow contraction of the superlattice. The distribution of lattice parameters and tilt angles was significantly larger for superlattices prepared by fast evaporation compared to slow evaporation of the solvent.

[OPEN POSITION]: PhD-position in solid state physics – X-ray and Neutron scattering

2017-04-07T13:48:00.002+02:00

PhD-position in solid state physics – X-ray and Neutron scattering

Published: 2017-04-04

Uppsala University is an international research university focused on the development of science and education. Our most important assets are all the individuals who with their curiosity and their dedication make Uppsala University one of Sweden’s most exciting work places. Uppsala University has 40,000 students, 7,000 employees and a turnover of SEK 6,5 billion.

A PhD-position in solid state physics – X-ray and Neutron scattering in the subject Engineering Science with specialization in the solid state physics, at the Ångström Laboratory, Department of Engineering Sciences, Division of Solid state physics (http://teknik.uu.se/solid-state-physics+/?languageId=3). Starting date as soon as possible.

This project will be conducted as part of a collaborative effort between Structural Chemistry and Solid State Physics, both situated at the Ångström Laboratory. The Ångström Advanced Battery Centre at Structural chemistry is the largest battery research group in the Nordic countries. Our research focuses on all aspects of the chemistry of rechargeable batteries; recently, we are looking at advanced nanomaterials with the aim of making energy storage more sustainable and cost-effective. The Magnetism group at the division of Solid State Physics is working with experimental research on novel magnetic materials, and has made key contributions to this research field. Apart from pursuing basic research on magnetic materials, the group is also involved in interdisciplinary research; developing magnetic nanoparticle based bioassays, and the study of the magnetization dynamics of self-assembled nanoparticle assemblies.

The PhD project will focus on the characterization of nanomaterials using neutron and X-ray scattering. The focal point of the project is the combination of scattering techniques at multiple length scales, in order gain insights in materials and processes by covering both the atomic- and the mesoscale. Several different materials will be explored throughout the project, including self-assembled magnetic nanomaterials and battery components. This work is funded by the Swedish research council, with the aim to develop several sample environments for the neutron diffractometer DREAM at the European spallation source (ESS). The work is performed in close collaboration with Stockholm University and involves travel to major facilities in EU and other parts of the world. We offer a varied and exciting work, with well-established collaboration with the department of Chemistry at the Ångström laboratory as well as with nationally and internationally renowned research groups.

We are seeking candidates with a MSc in engineering or science. A strong motivation and ability to work independently is desirable, and good verbal and written skills in English are required. Experience in materials science work will be considered as a merit.

The PhD position is for four years, extendable to a maximum of five years including departmental duties at a level of at most 20% (typically teaching).

Further information http://www.teknat.uu.se and http://www.teknik.uu.se.

Local guidelines for salary placement are used.

Uppsala University aims for gender balance and diversity in all activities in order to achieve a higher quality at all levels of the organization. We therefore welcome applicants of any gender and with different birth background, functionality and life experience.

Applications should include a brief description of research interests and relevant experience, a CV, copies of diplomas and certificates, thesis (or a draft thereof) and other relevant documents. The candidates are encouraged to provide letter(s) of recommendation and contact information to reference persons.

For further information please contact Dr Erik Wetterskog, +46-(0)18-471 3115, erik.wetterskog@angstrom.uu.se

You are welcome to submit your application no later than 25 April 2017, UFV-PA 2017/1102.

We decline offers of recruitment and advertising help. We only accept the application the way described in the advertisement.

Placement: Department of Engineering Sciences

Type of employment: Full time , Temporary position longer than 6 months

Pay: Fixed pay

Number of positions: 1

Working hours: 100 %

Town: Uppsala

County: Uppsala län

Country: Sweden

Union representative: Ellena Papaioannou, Seko 018-471 3315
Marie Ols, TCO/ST 018-471 2459
Per Sundman, Saco-rådet 018-471 1485

Number of reference: UFV-PA 2017/1202

Last application date: 2017-04-25

[OPEN POSITION] Postdoctoral Fellow in Materials Chemistry - Neutron Scattering

2017-04-07T13:44:00.000+02:00

Postdoctoral Fellow in Materials Chemistry - Neutron Scattering

Ref. No. SU FV-0992-17

at the Department of Materials and Environmental Chemistry. Closing date: 30 April 2017.

The Department of Materials and Environmental Chemistry at Stockholm University is one of the largest with about 150 persons working with the synthesis and structural characterisation of materials.

Project description
We are looking for a postdoc who can carry out research with neutron diffraction and SANS of nanomaterials with technical applications as biomaterials, battery components and potentially magnetic materials.

The project is a collaboration between Stockholm University, Uppsala University and the European Spallation Source (ESS) and has as a long-term plan to expand the neutron diffractometer DREAM at the ESS in Lund to study nanomaterials. Within the project, we will design different sample environments to enable the simultaneous acquisition of data in two length scales (atomic and nanoscopic). This will be used to study three different materials classes that have a strong research tradition in Sweden: biomaterials, batteries, and magnetic materials. In this way, the connection between the variations in the crystal structure and nanoparticle morphology can be established. Some examples of the possible studies include the self-assembly of small cellulose fibres, how the structure of batteries changes during usage, or how magnetic nanoparticles assemble under an applied magnetic field. The project is financed by the Swedish Research Council.

Main responsibilities
The postdoctoral fellow will work together with a team that will focus in studying different types of nanomaterials with neutron scattering at the atomic (diffraction) and nanoscopic (small angle neutron scattering, SANS) levels. The work implies comprehensive experiments with neutron scattering in neutron facilities around the world with the focus on the multiple length scale approach. The work also includes the design, development, and testing of different sample environments for the in-situ characterisation of two different types of nanomaterials such as nanocellulose and iron oxide nanoparticles.

Qualification requirements
Postdoctoral positions are appointed primarily for purposes of research. Applicants are expected to hold a Swedish doctoral degree or an equivalent degree from another country. The applicant should have a doctoral degree in chemistry or physics with a strong focus on condensed matter or similar qualifications.

Assessment criteriaThe degree should have been completed no more than three years before the deadline for applications. An older degree may be acceptable under special circumstances, such as sick leave, parental leave, clinical attachment, elected positions in trade unions, or similar.

In the appointment process special attention will be given to research skills. Documented experience of neutron scattering is required. Experience in X-ray scattering in general and total scattering in particular is advantageous.

Terms of employment
The position involves full-time employment for a maximum of two years, with the possibility of extension under special circumstances.

Stockholm University strives to be a workplace free from discrimination and with equal opportunities for all.

Contact
Further information about the position can be obtained from the PI, Assoc. Prof. German Salazar-Alvarez, telephone: +46 8 16 39 42, german@mmk.su.se, or Head of Department, Prof. Gunnar Svenson, telephone: +46 8 16 12 54, gunnar@mmk.su.se.

Union representatives
Anqi Lindblom-Ahlm (Saco-S) and Lisbeth Häggberg (Fackförbundet ST and Lärarförbundet), telephone: +46 8 16 20 00 (operator), and seko@seko.su.se (SEKO).

Application
Apply for the position at Stockholm University's recruitment system by clicking the "Apply" button. It is the responsibility of the applicant to ensure that the application is complete in accordance with the instructions in the job advertisement, and that it is submitted before the deadline.

Please include the following information with your application

Your contact details and personal data
Your highest degree
Your language skills
Contact details for 2–3 references

and, in addition, please include the following documents

Cover letter
CV – degrees and other completed courses, work experience and a list of publications
Research proposal (no more than 3 pages) describing:
– why you are interested in the field/project described in the advertisement
– why and how you wish to complete the project
– what makes you suitable for the project in question
Copy of PhD diploma
Letters of recommendation (no more than 3 files)
Publications in support of your application (no more than 3 files).

The instructions for applicants are available at: Instructions – Applicants.

Click here to apply!

Stockholm University – our education and research produce results.

URL to the original announcement pagehttp://www.su.se/english/about/vacancies/vacancies-new-list?rmpage=job&rmjob=3120&rmlang=UK

[Project Grant] Extended DREAM: Multiple-length scale approach to functional nanomaterials

2017-03-23T15:59:00.001+01:00

A team led by German Salazar-Alvarez, researcher at the Department of Materials and Environmental Chemistry, Stockholm University, has been awarded 10 MSEK by the Swedish Research Council, VR, to develop sample environments that will allow the in-situ and in-operando multiscale characterization of novel functional nanomaterials such as biomaterials, battery components, and magnetic nanoparticles. Coupled to the high brilliance of the ESS source the project will provide exceptional opportunities for the envisioned materials. Also, testing of the new sample environments at existing neutron facilities will promote the training of the Swedish community in neutron scattering.

Project "Extended DREAM: Multiple-length scale approach to functional nanomaterials”

Co-applicants:

- Kristina Edström, Uppsala University

- Werner Schweika, DREAM-ESS

- Gunnar Svensson, MMK-SU

- Peter Svedlindh and Erik Wetterskog, Uppsala University

Contact:

German Salazar-Alvarez

(german@mmk.su.se)

[OPEN ACCESS] A CaCO3/nanocellulose-based bioinspired nacre-like material

2017-03-16T17:50:00.000+01:00

Masoud Farhadi-Khouzani, Christina Schütz, Grażyna M. Durak, Jordina Fornell, Jordi Sort, Germán Salazar-Alvarez, Lennart Bergström and Denis Gebauer*

J. Mater. Chem. A, (2017)
DOI:10.1039/C6TA09524K

Abstract:
Nacre continues to be an inspiration for the fabrication of strong and tough materials from renewable and earth-abundant raw materials. Herein, we showed how a nacre-like hybrid material based on nanocellulose (NC) and CaCO3 can be prepared via the sequential infiltration of polymer-stabilised CaCO3 liquid precursors into layers of pre-deposited NC films. Layer-by-layer assembly of the NC films followed by controlled spreading and infiltration with liquid CaCO3 precursors generated a lamellar material with an architecture and iridescent appearance similar to those of nacre. The wettability of the NC films towards the liquid CaCO3 precursors was controlled by hydroxyl and carboxyl functionalization of the NC fibrils and the addition of magnesium ions. The combination of a high stiffness and plasticity of the nacre-like NC/CaCO3 hybrid materials show that excellent mechanical properties can be obtained employing a fibrillar organic constituent that is relatively hard. The fabrication of a nacre-like hybrid material via an aqueous route of assembly and infiltration processing demonstrates how a sustainable composite material with outstanding properties can be produced using the most abundant biopolymer and biomineral on earth.

Extensively interconnected silicon nanoparticles via carbon network derived from ultrathin cellulose nanofibers as high performance lithium ion battery anodes

2017-03-16T17:39:00.000+01:00

Jong Min Kim, Valentina Guccini, Kwang-dong Seong, Jiseop Oh, German Salazar-Alvarez*, Yuanzhe Piao*.

Carbon 118 (2017) 8–17
DOI: 10.1016/j.carbon.2017.03.028

Abstract:
Silicon is a good alternative to conventional graphite anode but it has bad cycling and rate performance. To overcome these severe problems, extensively interconnected silicon nanoparticles using carbon network derived from ultrathin cellulose nanofibers were synthesized. Ultrathin cellulose nanofibers, an abundant and sustainable material, entangle each silicon nanoparticle and become extensively interconnected carbon network after pyrolysis. This wide range interconnection provides an efficient electron path by decreasing the likelihood that electrons experience contact resistivity and also suppresses the volume expansion of silicon during lithiation. In addition, Ultrathin cellulose nanofibers are carboxylated and therefore adhesive to silicon nanoparticles through hydrogen bonding. This property makes ultrathin cellulose the perfect carbon source when making silicon composites. As a consequence, it exhibits 808 mAh g−1 of the reversible capacity after 500 cycles at high current density of 2 A g−1 with a coulombic efficiency of 99.8%. Even at high current density of 8 A g−1, it shows a high reversible discharge capacity of 464 mAh g−1. Moreover, extensively interconnected carbon network prevents the formation of a brittle electrode with a water-based binder. Therefore, this remarkable material has a huge potential for LIBs applications.

High-performance magnetic activated carbon from solid waste from lignin conversion processes. Part I: Their use as adsorbents for CO2

2017-03-11T20:18:00.001+01:00

Wenming Hao, Fredrik Björnerbäck, Yulia Trushkina, Mikel Oregui-Bengoechea, German Salazar-Alvarez, Tanja Barth, and Niklas Hedin

ACS Sustainable Chem. Eng., (2017)
DOI: 10.1021/acssuschemeng.6b02795

Abstract:
Lignin is naturally abundant and a renewable precursor with a potential to be used in the production of both chemicals and materials. As many lignin conversion processes suffer from a significant production of solid wastes in the form of hydrochars, this study focused on transforming hydrochars into magnetic activated carbons (MAC). The hydrochars were produced via hydrothermal treatment of lignins together with formic acid. The activation of the hydrochars was performed chemically with KOH with a focus on the optimization of the MACs as adsorbents for CO2. MACs are potentially relevant to carbon capture and storage (CCS) and gas purification processes. In general, the MACs had high specific surface areas (up to 2875 m2/g), high specific pore volumes, and CO2 adsorption capacities of up to 6.0 mmol/g (1 atm, 0 °C). The textual properties of the MACs depended on the temperature of the activation. MACs activated at a temperature of 700 °C had very high ultramicropore volumes, which are relevant for potential adsorption-driven separation of CO2 from N2. Activation at 800 °C led to MACs with larger pores and very high specific surface areas. This temperature-dependent optimization option, combined with the magnetic properties, provided numerous potential applications of the MACs besides of CCS. The hydrochar derived from eucalyptus lignin, and the corresponding MACs displayed soft magnetic behavior with coercivities of < 100 Oe and saturation magnetization values of 1-10 emu/g.

Following in real-time the two-step assembly of nanoparticles into mesocrystals in levitating drops

2016-10-28T20:58:00.002+02:00

Michael Agthe, Tomás S. Plivelic, Ana Labrador, Lennart Bergström, German Salazar-Alvarez

Nano Letters (2016)

DOI: 10.1021/acs.nanolett.6b02586

Abstract:

Mesocrystals composed of crystallographically-aligned nanocrystals are present in biominerals and assembled materials which show strongly directional properties of importance for mechanical protection and functional devices. Mesocrystals are commonly formed by complex biomineralisation processes and can also be generated by assembly of anisotropic nanocrystals. Here, we follow the evaporation-induced assembly of maghemite nanocubes into mesocrystals in real-time in levitating drops. Analysis of time-resolved small angle X-ray scattering data and ex-situ scanning electron microscopy together with interparticle potential calculations show that the substrate-free, particle-mediated crystallization process proceeds in two stages involving the formation and rapid transformation of a dense, structurally disordered phase into ordered mesocrystals. Controlling and tailoring the particle-mediated formation of mesocrystals could be utilized to assemble designed nanoparticles into new materials with unique functions.

Tunable high-field magnetization in strongly exchange-coupled freestanding Co/CoO core/shell coaxial nanowires

2016-08-12T11:47:00.000+02:00

German Salazar-Alvarez, Julian Geshev, Sebastia Agramunt-Puig, Carles Navau, Alvar Sanchez, Jordi Sort, and Josep Nogués

ACS Applied Materials and Interfaces, 2016
DOI: 10.1021/acsami.6b05588

Abstract:
The exchange bias properties of Co/CoO coaxial core/shell nanowires have been investigated with cooling and applied fields perpendicular to the wire axis. This configuration leads to unexpected exchange-bias effects. Firstly, the magnetization value at high fields is found to depend on the field-cooling conditions. This effect arises from the competition between the magnetic anisotropy and the Zeeman energies for cooling fields perpendicular to the wire axis. This allows imprinting pre-defined magnetization states to the AFM, as corroborated by micromagnetic simulations. Secondly, the system exhibits a high-field magnetic irreversibility, leading to open hysteresis loops, attributed to the AFM easy-axis reorientation during the reversal (effect similar to athermal training). A distinct way to manipulate the high-field magnetization in exchange-biased systems, beyond the archetypical effects, is thus experimentally and theoretically demonstrated.

[OPEN ACCESS] Tuning the structure and habit of iron oxide mesocrystals

2016-07-13T18:46:00.000+02:00

Erik Wetterskog*, Alice Klapper, Sabrina Disch, Elisabeth Josten, Raphaël P. Hermann, Ulrich Rücker, Thomas Brückel, Lennart Bergström and German Salazar-Alvarez*

Nanoscale (2016)
DOI: 10.1039/C6NR03776C

Abstract:
A precise control over the meso- and microstructure of ordered and aligned nanoparticle assemblies, i.e., mesocrystals, is essential in the quest of exploiting collective material properties for potential applications. In this work, we produce evaporation-induced self-assembled mesocrystals with different mesostructures and crystal habits based on iron oxide nanocubes by varying the nanocube size and shape, and by applying magnetic fields. A full 3D characterization of the mesocrystals was performed using image analysis, high-resolution scanning electron microscopy and Grazing Incidence Small Angle X-ray Scattering (GISAXS). This enabled structural determination of e.g. multi-domain mesocrystals with complex crystal habits, and the quantification of interparticle distances with sub-nm precision. Mesocrystals of small nanocubes (l = 8.6 – 12.6 nm) are isostructural with a body centred tetragonal (bct) lattice whereas assembly of the largest nanocubes in this study (l = 13.6 nm) additionally form a simple cubic (sc) lattice. The mesocrystal habit can be tuned from a square, hexagonal to star-like and pillar shapes depending on the particle size, shape, and the strength of the applied magnetic field. Finally, we outline a qualitative phase diagram of the evaporation-induced self-assembled superparamagnetic iron oxide nanocube mesocrystals based on nanocube edge length and magnetic field strength.

3D visualization of iron oxidation state in FeO/Fe3O4 core-shell nanocubes from electron energy loss tomography

2016-07-09T18:11:00.001+02:00

Pau Torruella, Raul Arenal, Francisco de la Peña*, Zineb Saghi, Lluís Yedra, Alberto Eljarrat, Lluis Lopez-Conesa, Marta Estrader*, Alberto López-Ortega, German Salazar-Alvarez, Josep Nogués Sanmiquel, Caterina Ducati, Paul A. Midgley, Francesca Peiró, and Sonia Estrade*

Nano Letters, 16 (2016) 5068-5073

DOI: 10.1021/acs.nanolett.6b01922

Abstract:
The physicochemical properties used in numerous advanced nanostructured devices are directly controlled by the oxidation states of their constituents. In this work we combine electron energy-loss spectroscopy, blind source separation, and computed tomography to reconstruct in three dimensions the distribution of Fe2+ and Fe3+ ions in a FeO/Fe3O4 core/shell cube-shaped nanoparticle with nanometric resolution. The results highlight the sharpness of the interface between both oxides and provide an average shell thickness, core volume, and average cube edge length measurements in agreement with the magnetic characterization of the sample.

[Workshop] Structure elucidation from molecular to macroscopic level

2016-04-28T20:29:00.001+02:00

Functional Hybrid Materials: structure elucidation from molecular to macroscopic level – A workshop and training school

Speakers and lecturers

Thomas Albrecht-Schmitt, Florida State University

Zoltán Bacsik, Stockholm University

Lennart Bergström, Stockholm University

Luís Carlos, University of Aveiro

Marie-Helene Delville, Institute of Chemistry of Condensed Matter of Bordeaux

Thierry Darmanin, University of Nice

Niklas Hedin, Stockholm University

Andrew Ken Inge, Stockholm University

Vadim Kessler, Swedish University of Agricultural Sciences

Nicholas Kotov, University of Michigan

Carita Kvarnström, University of Turku

Danielle Laurencin, Institute Charles Gerhard of Montpellier

Jean-Marie Nedelec, Institute of Chemistry of Clermont-Ferrand

Tomás Plivelic, MAX IV synchrotron

Meital Reches, Hebrew University of Jerusalem

João Rocha, University of Aveiro

German Salazar-Alvarez, Stockholm University

Nico Sommerdijk, Eindhoven University of Technology

Andreas Taubert, University of Potsdam

Wei Wan, Stockholm University

Max Wolff, Uppsala University

Xiaodong Zou, Stockholm University

The school aims at giving an overview of structure elucidation techniques relevant for the design of new hybrid materials. A recommendation of 1.5 ECTS will be given to students attending all lectures and presenting a poster. Deadline registration April 30th, 2016.

Registration free of charge. Details at http://www.tinc.nu/

Organizers

German Salazar-Alvarez, Stockholm University

Vadim Kessler, Swedish University of Agricultural Sciences

Thin Water Films at Multifaceted Hematite Particle Surfaces

2016-01-11T22:25:00.000+01:00

Jean-François Boily, Merve Yeşilbaş, Munshi Md. Musleh Uddin, Lu Baiqing, Yulia Trushkina, and Germàn Salazar-Alvarez

Langmuir, 31 (2015) 13127–13137
DOI: 10.1021/acs.langmuir.5b03167

Abstract:
Mineral surfaces exposed to moist air stabilize nanometer- to micrometer-thick water films. This study resolves the nature of thin water film formation at multifaceted hematite (α-Fe2O3) nanoparticle surfaces with crystallographic faces resolved by selected area electron diffraction. Dynamic vapor adsorption (DVA) in the 0–19 Torr range at 298 K showed that these particles stabilize water films consisting of up to 4–5 monolayers. Modeling of these data predicts water loadings in terms of an “adsorption regime” (up to 16 H2O/nm2) involving direct water binding to hematite surface sites, and of a “condensation regime” (up to 34 H2O/nm2) involving water binding to hematite-bound water nanoclusters. Vibration spectroscopy identified the predominant hematite surface hydroxo groups (−OH, μ–OH, μ3–OH) through which first layer water molecules formed hydrogen bonds, as well as surface iron sites directly coordinating water molecules (i.e., as geminal η–(OH2)2 sites). Chemometric analyses of the vibration spectra also revealed a strong correspondence in the response of hematite surface hydroxo groups to DVA-derived water loadings. These findings point to a near-saturation of the hydrogen-bonding environment of surface hydroxo groups at a partial water vapor pressure of ∼8 Torr (∼40% relative humidity). Classical molecular dynamics (MD) resolved the interfacial water structures and hydrogen bonding populations at five representative crystallographic faces expressed in these nanoparticles. Simulations of single oriented slabs underscored the individual roles of all (hydro)oxo groups in donating and accepting hydrogen bonds with first layer water in the “adsorption regime”. These analyses pointed to the preponderance of hydrogen bond-donating −OH groups in the stabilization of thin water films. Contributions of μ–OH and μ3–OH groups are secondary, yet remain essential in the stabilization of thin water films. MD simulations also helped resolve crystallographic controls on water–water interactions occurring in the “condensation regime”. Water–water hydrogen bond populations are greatest on the (001) face, and decrease in importance in the order (001) > (012) ≈ (110) > (014) ≫ (100). Simulations of a single (∼5 nm × ∼ 6 nm × ∼ 6 nm) nanometric hematite particle terminated by the (001), (110), (012), and (100) faces also highlighted the key roles that sites at particle edges play in interconnecting thin water films grown along contiguous crystallographic faces. Hydroxo–water hydrogen bond populations showed that edges were the preferential loci of binding. These simulations also suggested that equilibration times for water binding at edges were slower than on crystallographic faces. In this regard, edges, and by extension roughened surfaces, are expected to play commanding roles in the stabilization of thin water films. Thus, in focusing on the properties of nanometric-thick water layers at hematite surfaces, this study revealed the nature of interactions between water and multifaced particle surfaces. Our results pave the way for furthering our understanding of mineral-thin water film interfacial structure and reactivity on a broader range of materials.

Controlled molecular reorientation enables strong cellulose fibers regenerated from ionic liquid solutions

2015-09-01T21:26:00.001+02:00

Johan Sundberg, Valentina Guccini, Karl M.O. Håkansson, German Salazar-Alvarez, Guillermo Toriz, Paul Gatenholm

Polymer 75 (2015) 119-124.
DOI: 10.1016/j.polymer.2015.08.035

Highlights:
• Strong cellulose fibers spun from ionic liquid solution.
• Extrusion process simulated in silica based upon rheological measurements.
• Increased DO for fibers regenerated with ethanol stretched at high RH.
• Significant improvement of mechanical properties for re-oriented fibers.
• Mechanical properties comparable to commercially available fibers.

Abstract:
Cellulose is difficult to solubilize and undergoes thermal decomposition prior to melting. In recent years ionic liquids have been evaluated as solvents of cellulose. In the regeneration process the non-solvent governs the resulting material's crystallinity. Water adsorbs to amorphous cellulose, acts as plasticizer and lowers the Tg, hence the degree of crystallinity will affect the potential strain induced reorientation. We prepared regenerated cellulose fibers form ionic liquid using different non-solvents. The influence of shear forces upon cellulose chain alignment during extrusion was simulated in silica based upon rheological measurements. The regenerated fibers had different physical, morphological and mechanical properties. Molecular re-orientation in fibers induced by mechanical strain, at humidities above the Tg, resulted in much improved mechanical properties with the Young's modulus reaching 23.4 ± 0.8 GPa and the stress at break 504.6 ± 51.9 MPa, which is comparable to commercially available cellulose fibers.

[OPEN ACCESS] Rod Packing in Chiral Nematic Cellulose Nanocrystal Dispersions Studied by Small-Angle X-ray Scattering and Laser Diffraction

2015-07-02T18:38:00.000+02:00

Christina Schütz, Michael Agthe, Andreas B. Fall, Korneliya Gordeyeva, Valentina Guccini, Michaela Salajková, Tomás S. Plivelic, Jan P. F. Lagerwall, German Salazar-Alvarez, and Lennart Bergström
Langmuir 31 (2015) 6507–6513.
DOI: 10.1021/acs.langmuir.5b00924

Abstract

The packing of cellulose nanocrystals (CNC) in the anisotropic chiral nematic phase has been investigated over a wide concentration range by small-angle X-ray scattering (SAXS) and laser diffraction. The average separation distance between the CNCs and the average pitch of the chiral nematic phase have been determined over the entire isotropic–anisotropic biphasic region. The average separation distances range from 51 nm, at the onset of the anisotropic phase formation, to 25 nm above 6 vol % (fully liquid crystalline phase) whereas the average pitch varies from ≈15 μm down to ≈2 μm as ϕ increases from 2.5 up to 6.5 vol %. Using the cholesteric order, we determine that the twist angle between neighboring CNCs increases from about 1° up to 4° as ϕ increases from 2.5 up to 6.5 vol %. The dependence of the twisting on the volume fraction was related to the increase in the magnitude of the repulsive interactions between the charged rods as the average separation distance decreases.

[OPEN ACCESS] Fabrication of nanocellulose–hydroxyapatite composites and their application as water-resistant transparent coatings

2015-06-30T14:03:00.000+02:00

Mai Ishikawa, Yuya Oaki, Yoshihisa Tanaka, Hideki Kakisawa, German Salazar-Alvarez and Hiroaki Imai

J. Mater. Chem. B, 2015, Advance Article
DOI: 10.1039/C5TB00927H

Abstract
Nanosized composite rods ~300 nm in length and ~20 nm in width were produced by deposition of 22–77 wt% of a c-axis-oriented hydroxyapatite (HA) on cellulose nanocrystals (CNCs). The CNCs functionalized with sulphonic groups were covered with the HA nanocrystals through controlled nucleation and growth under a moderately supersaturated condition in a solution system based on a simulated body fluid. Water-resistant transparent coatings 2–4 μm thick were obtained via evaporation-induced assembly of CNC–HA nanocomposites by casting their suspension on a glass substrate and the subsequent growth of HA nanocrystals by vapour hydrothermal treatment. The composite coatings exhibited improved mechanical strength compared to that of crustacean exoskeletons, and potential for bone regeneration.

[PhD defence] Christina Schütz – Fabrication of nanocellulose-based materials - Liquid crystalline phase formation and design of inorganic–nanocellulose hybrids

2015-05-15T01:09:00.000+02:00

Christina Schütz has (literally) nailed her thesis and the dissertation will be on May 29th (See link). The full text of the thesis can be found at DiVA.

[REVIEW] [OPEN ACCESS] Mesocrystals in Biominerals and Colloidal Arrays

2015-05-10T19:54:00.000+02:00

Lennart Bergström, Elena V. Sturm (née Rosseeva), German Salazar-Alvarez, and Helmut Cölfen

Accounts of Chemical Research (2015)

DOI: 10.1021/ar500440b

Abstract

Mesocrystals, which originally was a term to designate superstructures of nanocrystals with a common crystallographic orientation, have now evolved to a materials concept. The discovery that many biominerals are mesocrystals generated a large research interest, and it was suggested that mesocrystals result in better mechanical performance and optical properties compared to single crystalline structures. Mesocrystalline biominerals are mainly found in spines or shells, which have to be mechanically optimized for protection or as a load-bearing skeleton. Important examples include red coral and sea urchin spine as well as bones. Mesocrystals can also be formed from purely synthetic components. Biomimetic mineralization and assembly have been used to produce mesocrystals, sometimes with complex hierarchical structures. Important examples include the fluorapatite mesocrystals with gelatin as the structural matrix, and mesocrystalline calcite spicules with impressive strength and flexibility that could be synthesized using silicatein protein fibers as template for calcium carbonate deposition. Self-assembly of nanocrystals can also result in mesocrystals if the nanocrystals have a well-defined size and shape and the assembly conditions are tuned to allow the nanoparticles to align crystallographically. Mesocrystals formed by assembly of monodisperse metallic, semiconducting, and magnetic nanocrystals are a type of colloidal crystal with a well-defined structure on both the atomic and mesoscopic length scale.

Mesocrystals typically are hybrid materials between crystalline nanoparticles and interspacing amorphous organic or inorganic layers. This structure allows to combine disparate materials like hard but brittle nanocrystals with a soft and ductile amorphous material, enabling a mechanically optimized structural design as realized in the sea urchin spicule. Furthermore, mesocrystals can combine the properties of individual nanocrystals like the optical quantum size effect, surface plasmon resonance, and size dependent magnetic properties with a mesostructure and morphology tailored for specific applications. Indeed, mesocrystals composed of crystallographically aligned polyhedral or rodlike nanocrystals with anisotropic properties can be materials with strongly directional properties and novel collective emergent properties. An additional advantage of mesocrystals is that they can combine the properties of nanoparticles with a structure on the micro- or macroscale allowing for much easier handling.

In this Account, we propose that mesocrystals are defined as “a nanostructured material with a defined long-range order on the atomic scale, which can be inferred from the existence of an essentially sharp wide-angle diffraction pattern (with sharp Bragg peaks) together with clear evidence that the material consists of individual nanoparticle building units”. We will give several examples of mesocrystals and discuss the structural characteristics for biominerals, biomimetic materials, and colloidal arrays of nanocrystals. The potential of the mesocrystal materials concept in other areas will be discussed and future developments envisioned.