Materials for Renewable Energy NaturE's Way (RENEW)

Lead Research Organisation: University of Sheffield
Department Name: Materials Science and Engineering


At current rates of consumption, many of the materials we use to make today's clean energy technologies could be scarce or gone in decades or less. Furthermore, improving the performance of materials for clean energy generation, resulting in higher efficiency processes, remains a critical need. PIRE: RENEW will use biological-based materials to both improve material performance and create sustainable replacements in clean energy technologies, focusing on applications such as solar and wind power rather than liquid fuel. An international research program will be built around this focus. This program will draw together the interdisciplinary expertise necessary to develop replacements that provide improvements in function, consider current and future global raw material availability, and are designed to mitigate environmental impact both in production and disposal. Students involved in this research will be trained in an interdisciplinary and global approach to sustainability problem solving. Together, these elements will allow PIRE: RENEW to create an international research nexus, one that can provide advanced sustainable material solutions for a broad range of energy technology challenges, and educate students to be valuable for industry and academic paths.
Intellectual Merit: PIRE: RENEW's research will explore the use of naturally derived and other biobased materials in renewable energy applications where intermolecular and interfacial interactions play a key role in self-assembly and aggregation, in building structural materials with exceptional properties, and in nanoscale optoelectronics. To carry out this vision, interdisciplinary research will:
- Explore building wind turbine blades from biobased nanocomposites with engineered interfaces consisting of cellulose nanofibers and biobased epoxy thermoset and polyester thermoplastic matrix materials. These innovative biobased nanocomposites will be compared with nanocomposites consisting of biobased or petroleum-derived resins and functionalized carbon nanotubes.
- Explore molecular and supramolecular structure-property relationships relevant for charge transport and transfer in self-organized molecular dendron and electronically functionalized biobased cellulose nanowhiskers, bacterial cellulose fibrils, and sophorolipid surfactants for solar energy applications
Need for International Partnership: New sustainable materials from readily-renewable carbon sources developed in the Gross research lab (NYU-POLY) with collaborators (UMONS, Bologna) provide the critical research nexuses with the wind energy research of Manas and collaborators (CWRU, Santa Catarina) and the solar energy research of Singer and collaborators (CWRU, Penn, Sheffield). Only through the connection of these international partners is the research vision achievable, as it requires specific expertise and facilities of i) materials synthesis (Gross, Percec), ii) processing (Manas, Singer, Percec, Dubois, Pezzin, Fontana, Coelho), and iii) characterization (Ungar, Scandola, Manas, Singer) to create its intended materials - as well as to provide students an international/interdisciplinary education.
Broader Impact: The new materials and understandings created could apply to sustainability outside energy (e.g., consumer products). Faculty lectures given at international locations will be open to students outside the PIRE, both in person and in posting to the Internet. A website and legacy of web-based educational materials created by the PIRE team will share its research and give the opportunity to the scientific community to respond through posts, project ideas, video, etc. The website will also publish a clearinghouse of gathered links/articles on sustainable materials and renewable energy applications. "Sustainability challenges" taken on by student teams with input from business, policy, and environment faculty will also be written up as educational modules.

Planned Impact

Our integration of research and education revolves around extended international exchanges for post graduate students and PDRAs, and on an ongoing series of educational mechanisms that include these graduate students, undergraduates, and - when appropriate - external experts. The following mechanisms will build teams across levels of experience and disciplines, as well as broadly communicate

A website will be created with levels of access that will serve multiple constituencies with interest in sustainable materials.

Students and PDRAs will be engaged in learning how to bridge disciplinary and spoken languages.

Students will solve "sustainability challenges" in simulated exercises conceptualized with experts from outside the PIRE faculty team. Challenges will come from experts in business, policy, or the environment.

U.S. partner institutions will design and host multi-day meetings on the PIRE work at their university during the five years. All U.S. students and faculty will attend, and all foreign faculty and students will be invited - leveraging international funding outside of PIRE - or will be involved by webinar/videoconferencing.


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Description The Sheffield team has published 35 publications resulting from the research under the PIRE "Renew" project (EP-K034308), of which 29 are scientific journal papers and one is a book chapter. Further papers are in preparation. The scientific output is exceptional. Most papers are published in top level journals: 1 in Nat. Chem., 1 in Nat. Commun., 4 in Angew. Chem., 7 in JACS, 2 in ACS Nano. The average journal impact factor of the 29 papers is 9.11, and the cumulative impact SUM(ni*IFi) = 255. 6 of the above papers are featured on the journal cover (4 front and one inside). These papers are:
• C. Dressel et al. Angew. Chem. Int. Ed., 2014, 53, 13115.
• C. Tschierske, G. Ungar. ChemPhysChem 2016, 17, 9.
• X.S. Hu et al. J. Am. Chem. Soc. 2018, 140, 1805.
• H.J. Lu et al. Angew. Chem. Int. Ed. 2018, 57, 2835
• W. D. Stevenson et al. Soft Matter 2018 2018, 14, 3003
. C. Nürnberger et al. Chem. Comm. 2019, DOI: 10.1039/C9CC00494G

Some of the key scientific results are listed below.

1. Perylene bisimes were synthesised by Percec's team, having trialkoxyphenyl groups with branches in the alkyl chains, both chiral and racemic. The role of chirality on helical order was investigated. A crystalline helical structure was obtained through controlled melt processing with unprecedented high order, as determined by fibre diffraction. This structure is formed through controlled processing via a more disordered columnar LC precursor, ensuring both orientability and lack of grain boundaries. Preliminary structural model was proposed and is being verified.
2. Discovery of the first honeycomb structure in an organic semiconductor.
3. Observation of unique morphologies in complexes between polymers carrying acceptor sidegroups and dendronized electron donors by high-resolution high temperature AFM, small and intermediate angle XRD, and grazing incidence diffraction.
4. Completion of 2 chapters in Handbook of Liquid Crystals, 2nd Ed., Vol. 5, J.W. Goodby et al. eds., VCH_Wiley, entitled: "Thermotropic Cubic Liquid Crystal Phases, Other 3D Phases and Quasicrystals", and "Side-branched Polyphiles and Polygonal Cylinder Phases".
5. Completion of "X-Ray Scattering", Chapter 6 in Liquid crystals with nano- and microparticles, Vol. 1, ed. J. Lagerwall and G. Scalia, World Scientific, Singapore 2016.
6. Completion of an in-depth study of molecular organization of dendronized cyclotriveratrylenes (CTV) using circular dichroism and UV/vis spectroscopy, X-ray fiber diffraction and solid-state NMR. Demonstrated how self-sorting of chiral enantiomers (deracemization) occurs and helical organization develops. We also showed how molecular tilt, and thus pi-pi stacking, can be controlled by chain branching.
7. Arrived at a thorough understanding of the complexities of arrangement of LC and soft-crystal columns in nanochanels of circular and polygonal cross-sections. Corrected some misleading concepts in previous literature and established design principles for device materials using nanoconfined columnar semiconductors and photo-active cells.
8. Discovered a new type of bicontinuous cubic LC phases, where the rod-like molecules align parallel rather than normal to the segments of the infinite interpenetrating networks.
9. Discovery that all networks in bicontinuous phases of cubic and other symmetries in polycatenar compounds (rod-like with several terminal chains) are made up of helical segments. Moreover the entire network is homochiral (same helical sense) even if the compounds are not chiral. The homochirality propagates to infinity due to the requirement of homochirality of converging segments at network junctions. This leads to overall chirality (strong optical activity) in all cases of the triple network Im3m cubic phase, but no chirality in any example of the double gyroid Ia3d phase, where the opposite chiralities of its two networks cancel. Such phases are now being investigated as possible alternatives to columnar organic semiconductors ("molecular wire networks"), removing the need for alignment.
10. Solution of the 30-year problem of the "Smectic-Q" phase. Contrary to previous models, the phase turns out to be a bicontinuous one, made up of two isochiral networks of helical column segments, aligned along x, y and z axes, with 4-way junctions. The phase has previously been found only in highly enantiopure chiral compounds. We observe it in non-chiral compounds, where the chirality is induced by spontaneous self-assembly. The fact that the phase forms only in highly enantiopure chiral compounds or in compounds that are not chiral at all illustrates the high defect energy of incorporating a molecule of wrong handedness into a network of opposite twist.
11. Realization of a new type of columnar soft crystals of dendronized perylene bisimide (PBI) with unprecedented high order, which also form quite easily and quickly, without the need of special annealing treatment. This achievement was a result of a systematic study of numerous PBI derivatives, and in this case using branched chiral alkyl chains which include homochiral, racemate and a series of 21 diastereomers prepared by the Upenn group and studied jointly by them and the Sheffield group. The key to the high order is the unique "cogwheel" structure of interlocking helical columns. In this double helix structure the peripheral chains are parallel to the column and their length matches exactly the helical half-pitch thus virtually eliminating helix reversal defects.
12. Discovery of the first example of the double-diamond bicontinuous cubic structure in thermotropic liquid crystals. Its detailed structure was determined and arrived at a rational physical model was proposed connecting the phase structure with the structure of the molecules.
13. The widespread phenomenon of lateral thermal shrinkage of supramolecular columns was investigated. It was found that such shrinkage is facilitated by the addition of free n-alkanes. By using deuterated alkanes and a combination of x-ray and neutron diffraction, the alkane was shown to aggregate preferentially in vacancies left by the dendron molecules expelled from the column on heating. Surprisingly, this leads to the formation of regular 2-D superlattices, a phenomenon that could possibly be exploited in building functional molecular arrays with large periods using only small molecules. Such columns, containing alkali metal salts, can be used as 1-D ionic conductors, with possible uses in rechargeable batteries. It was also found that, if suitably designed, in such self-assemblies ionic arrays conductivity can be switched on and off reversibly upon a thermal transition between the ordered rectangular and the disordered hexagonal columnar phase.
14. Realization of the first low symmetry 3D array of quantum dots, allowing mesostructure-dependent energy transfer. The structure is a new cubic liquid crystal phase and its unusually low P213 symmetry is also unprecedented as a packing mode of spherical objects. Once fully organized, the array exhibits 'high light absorption, low re-emission' properties which are important in the design of light harvesting devices such as solar cells. This mode of self-assembly of QDs is achieved through the specific double-shell design of the soft corona engulfing the particle. This work demonstrates that the key to accessing new and more interesting 3D arrays is the design of the molecular shell around the spherical particle.
15. The utility was demonstrated of in-situ real-time synchrotron small-angle X-ray scattering in directly monitoring diffusion in and out of hollow nanoparticles. The particles were TiO2, and the work is relevant to their use as drug carriers and catalysts. They can also be used as markers to enable in-situ SAXS monitoring of diffusion of water and chemicals into a polymer matrices of various irregular shapes.
16. Using resonant X-ray scattering we have proven the heliconical model of the "twist-bend" nematic (Ntb) phase in bent LC dimers. We have also confirmed the first example of the Ntb phase in a polymer.
Exploitation Route Our results help design organic semiconducting materials with high charge mobility and add new insights into molecular self-assembly on the nanoscale.
Sectors Chemicals,Digital/Communication/Information Technologies (including Software),Electronics,Energy

Description 1. A range of new organic semiconducting photoactive compounds with cores based on bisimides of perylene, pyrene, naphtalene and others have been synthesised by our partners at University of Pennsylvania. The structure and properties of their soft columnar crystals was studied extensively in Sheffield. From the application point, two issues are particularly worth highlighting. - The structure can be made helical and homochiral, making the materials potentially suitable for handling circularly polarized (CP) light, e.g. for high-contrast displays (e.g. AMOLED), optical communication and quantum computing. - Soft columnar crystals of unprecedented perfection were obtained through a unique design using branched side-chains of precisely selected length, supporting a particularly robust helical structure with no helix reversals. This "cogwheel" principle, described in Nature Chemistry 2016, 8, 80 ( makes it possible to combine two previously incompatible requirements of efficient charge mobility transport in liquid crystals and soft organic crystals, i.e. crystal perfection and self-healing of grain boundaries. 2. Also in order to be able to manipulate CP light, we prepared (in collaboration) and successfully proved that we achieved the first helical array of gold nanoparticles. We used the nanoparticles grafted with cholesterol-based ligands and proved the above structure by XRD and circular dichroism spectroscopy. This opens the way of creating plasmonic systems interacting specifically with CP light (see above for potential applications) (J. Am. Chem. Soc. 2015, 137, 12736 3. Another advance made within the project that involves nanoparticles is the finding that newly sysnthesised CdS quantum dots coated with a special double-corona of inner alkyl and outer dendron ligands form a novel low-symmetry ordered cubic array. This nanostructure contains pi-conjugated pathways of aromatic dendrons that allow efficient transport of energy from absorbed light. The tailorable self-organization and 'high absorption, low re-emission' properties of the ordered 3-D array may prove to be a promising advance towards more efficient solar cells, where re-emission of absorbed light is undesirable. The luminescence quenching property is determined by the nanostructure and can be turned on and off by annealing and melt-quenching (Chem (Cell), 2, 2017, 860, 4. A major breakthrough is the discovery that inorganic clusters (polyoxymetalate and silsesquioxane - POSS), tethered by an organic spacer, synthesised by our partners, form isolated single, double and triple layers in solution. These layers have a highly porous hexagonal honeycomb structure and are the nanoscale self-assembled equivalents of graphene. These 2D metal-organic frameworks could open a new chapter in MOF materials. They possess unparalleled surface area and are highly likely to be developed into very efficient catalysts (J. Am. Chem. Soc. 2018, 140, 1805-1811. 5. We successfully applied resonant X-ray diffraction at the Se K-edge to prove that the low-temperature nematic phase in dimers with odd-numbered methylene spacers indeed has a helical structure, with a 10 nm pitch (the "twist-bend nematic", Ntb, as predicted by some recent theories. Furthermore, we have shown the first example of a helical Ntb polymer. The application potential of the Ntb phase in dimers is in fast displays due to the high reversibility and speed of Ntb-N switching, while that of Ntb polymers is two-fold. (a) A naturally helical structure could yield high impact (high toughness) polymers in a similar fashion as the zigzag structure of Nomex aramid yields a much tougher polymer than the straight-chain Kevlar. (b) We envisage that a Ntb elastomer could be produced through cross-linking, with yet unforeseen and unusual mechanical properties, yet to be explored (Phys. Chem. Chem. Phys 2017, 19 13449; Soft Matter publ. online 27 Feb. 2018 6. Through a series of detailed studies by optical, XRD and high-resolution AFM techniques, we have clarified the alignment behaviour of columnar liquid crystals of nearly all types in cylindrical nano- and micro-confinement. Nano- and microchannels in hard templates, such as anodic alumina (AAO), have been expected to facilitate column alignment along the pore axis and thus produce bundles of semiconducting wires using pi-conjugation along the columns (z-axis). However, it turned out that the columns of most liquid crystals resist axial alignment and prefer to organize within the xy plane, i.e. perpendicular to the pore axis. Our studies have shown that the reason for not aligning axially is that this would lead to an energetically costly distortion of the hexagonal lattice. To prove this, we prepared channels with different polygonal sections by deep reactive ion etching and found that columns of a square phase align axially in square channels, and hexagonal columns do the same in triangular channels. This new knowledge will be very valuable in designing devices based on columnar liquid crystals, such as in light harvesting, OLEDs, field-effect transistors and gas and vapour sensors ("electronic nose"). (ACS Nano, 2014, 8, 4000 http://doi/org/10.1021/nn406368e; ACS Nano, 2015, 9, 1759-1766.; Soft Matter, 2017, 13, 4122; R.B. Zhang et al. "Square and hexagonal columnar liquid crystals confined in square and triangular pores", .Adv. Funct. Mater. 2019, 29(3) 1806078 7. We discovered a new cubic phase - the first Single Diamond bicontinuous phase in soft matter (Angew. Chem. Int. Ed. 2019. The phase is obtained in rod-like "bolaamphiphiles" with swallow-tailed branched side-chains. Theoretical studies indicate that this structure is an ideal photonic crystal. Scale up to photonic dimension is expected to bring this structure to real applicable material obtained entirely through bottom-up self-assembly. 8. We have successfully created rectangular and square sub-10 nm honeycomb grids, as well as more complex "chessboard" and "snub-square" nanopatterns through self-assembly of bolaamphiphile molecules (Chem. Comm. 2019, These nano-honeycombs are particularly suitable for nano-electronic patterning due to their rectangular and square grids and to their zero thermal expansion coefficient. 9. Additionally, we have contributed to different sub-projects lead by our partners at Case Western Reserve University (CWRU) and Rensselaer Polytechnic Institute (RPI). We have determined the structures of several solar cell materials based on aromatic pi-stacked cores and biobased sophorolipid side-chains. Developments toward commercialization of these materials are still in progress, although it has become apparent that their price, currently double that of the more conventional oil-based materials, is a hindrance under current market conditions. We have also contributed, mainly using high-resolution AFM, to the development of biocomposite materials primarily aimed for use in wind turbine blades. These use light-weight bacterial cellulose nanofibers that are surface-functionalized for compatibility with matrix resins. Work on commercialization of these environmentally friendly materials is currently in progress.
First Year Of Impact 2019
Sector Chemicals,Education
Impact Types Cultural,Economic

Description EPSRC Responsive Mode
Amount £342,342 (GBP)
Funding ID EP-P002250 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 01/2018 
End 01/2021
Description Case Western 
Organisation Case Western Reserve University
Country United States 
Sector Academic/University 
PI Contribution This grant is a collaboration with Case Western Reserve University, Cleveland, Ohio, USA, Professors Ica Manas and Ken Singer, and University of Pennsylvania, Philadelphia, USA, Prof. Virgil Percec, as part of this joint NSF-EPSRC grant. Collaboration with Prof. Singer was on electrical properties of columnar liquid crystals and Prof Percec's group synthesised and supplied new semiconducting liquid crystal materials.
Collaborator Contribution Prof. Singer's group performed electro-optic measurements on materials studied by us by other techniquies, primarily X-ray diffraction. Two students from CWRU spent a month each in our laboratory during summer. Prof Percec supplied perylene bisimide-based compounds and did analytical work and part of structural studies.
Impact A number of articles in high-impact journals were published jointly, including Nature Chemistry, JACS etc.
Start Year 2013
Description Halle 
Organisation Martin Luther University of Halle-Wittenberg
Country Germany 
Sector Academic/University 
PI Contribution Structural and Physical studies.
Collaborator Contribution Synthesis of functional materials and their chemical characterization.
Impact A number of high-profile papers including in Nature Commun, Angew. Chem. Front cover of Abgew, Chem, and ChemPhysChem.
Start Year 2013
Description Upenn 
Organisation University of Pennsylvania
Country United States 
Sector Academic/University 
PI Contribution Physical and structural studies on materials supplied by Prof. Percec's group
Collaborator Contribution Prof. Percec's group supplied compounds mainly based on perylene bisimide for our physical and structural studies.
Impact Several high-profile papers incl. in Nature Chemistry and JACS
Start Year 2013