Azobenzene Lyotropic Liquid Crystals as Photoswitchable Materials for Solar Thermal Fuels

Lead Research Organisation: University of Cambridge
Department Name: Materials Science & Metallurgy

Abstract

This project will investigate the opportunity for lyotropic liquid crystal (LLC) assemblies of azobenzene-photosurfactants (AzoPS) as high energy storage STFs for the first time. It has recently been shown that neutral AzoPS form a variety of LLC phases, which can be accessed at low concentrations (10 wt%) through strategic design of the molecular structure. The LLC mesophases could be destroyed upon UV irradiation and re-assembled under blue light (or heat). The AzoPS LLCs could offer enhanced energy storage density for STFs due to the combination of increased intermolecular interactions and a high chromophore density. The key focus will be to determine the energy storage density. To understand this new material design space, the project will tune molecular packing by using: different LLC mesophases, co-dilution with a regular surfactant, and solvent.

Combined structural, spectroscopy and thermal characterisation will be used to correlate changes in the photoswitch state, to structural packing and the energy storage density. Attention will be paid to understanding the heterogeneity, kinetics and energetics of photoisomerisation in AzoPS LLCs using small-angle X-ray scattering (SAXS) and infrared spectroscopy to design system with high energy storage density.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/R513180/1 01/10/2018 30/09/2023
2438208 Studentship EP/R513180/1 01/10/2020 30/09/2024 Beatrice Jones
EP/T517847/1 01/10/2020 30/09/2025
2438208 Studentship EP/T517847/1 01/10/2020 30/09/2024 Beatrice Jones
 
Description 1. We have designed and implemented a new method for in-situ LED light irradiation during small-angle X-ray scattering experiments at Beamline B21, Diamond Light Source. This will enable future experiments in this project to determine the mechanisms for light-responsive changes in our materials. It will also enable future collaborations with other scientists studying light-responsive systems.
2. We have created the first example of light-responsive cubic lyotropic liquid crystal dispersions, which have been used to release small molecules on-demand. These particles could have future applications in targeted delivery of drugs, pesticides or catalysts.
3. We have started a collaboration with Imperial College, London (Jake Greenfield and Matthew Fuchter) to characterise the self-assembly of a new set of photoswitchable surfactants. This has led to the discovery of the first light-responsive order-to-order phase change in a lyotropic liquid crystal. The full potential of applications is still unknown, but it is thought this could be used as a on-off switchable permeable barrier.
4. We have characterised a new set of light-responsive lyotropic liquid crystals and how they change when they are irradiated with UV light. We are still investigating the potential for energy storage using the phase changes for application as a solar thermal fuel.
Exploitation Route In the next 1.5 years of this project, the focus will be on applying the lessons learned so far to applications as a solar thermal fuel. This will enable us to determine whether solar energy can be stored in these materials and subsequently released as heat.
Further projects, perhaps involving future PhD or Masters' students, could investigate the potential for the cubic liquid crystal particles as drug- or catalyst-delivery materials.
Sectors Agriculture, Food and Drink,Chemicals,Energy,Environment,Pharmaceuticals and Medical Biotechnology
 
Title Research data supporting Light-Responsive Molecular Release from Cubosomes Using Swell-Squeeze Lattice Control 
Description Data files contain the raw data for the Figures in the manuscript and SI. Fig2a contains the raw SAXS XY data for bulk LLC phases of MO-water (20 wt%), MO-C6AzoC4E4 (20 wt%)-water (20 wt%) and MO-C8AzoC8E4 (20 wt%)-water (20 wt%). Columns are q (Å-1), intensity (C6AzoC4E4), intensity (C8AzoC8E4) and intensity (MO). Fig2b contains the POM micrograph for a bulk LLC phase of MO- C6AzoC4E4 (20 wt%)-water (20 wt%). Fig 2c contains the POM micrograph for a bulk LLC phase of MO- C8AzoC8E4 (20 wt%)-water (20 wt%). $$ \ $$ Fig3a contains the cryo-TEM micrograph for a dispersion of MO-water (20 wt%). The scale bar indicates 100 nm. Fig3b contains the cryo-TEM micrograph for a dispersion of MO-C6AzoC4E4 (20 wt%)-water (20 wt%). The scale bar indicates 100 nm. Fig3c contains the raw SAXS XY data for dispersions containing MO-water (20 wt%), MO-C6AzoC4E4 (10 wt%)-water (20 wt%) and MO-C8AzoC8E4 (10 wt%)-water (20 wt%) at 25 °C. Columns are q (Å-1), intensity (MO), intensity (C6AzoC4E4) and intensity (C8AzoC8E4). Fig 3d contains the raw SAXS XY data for dispersions containing MO-C8AzoC8E4-water of varying concentration of C8AzoC8E4 and water. Columns are q (Å-1) and intensity for: 10 wt% water, 10 wt% C8AzoC8E4; 20 wt% water, 10 wt% C8AzoC8E4; 30 wt% water, 10 wt% C8AzoC8E4; 40 wt% water, 10 wt% C8AzoC8E4; 20 wt% water, 20 wt% C8AzoC8E4; 20 wt% water, 0 wt% C8AzoC8E4; 20 wt% water, 30 wt% C8AzoC8E4. Fig3e contains the XY data for lattice parameter vs. initial water concentration and AzoPS concentration. Columns are: initial water concentration (wt%); lattice parameter - C6AzoC4E4 (Å); y error; lattice parameter - C8AzoC8E4 (Å); y error; AzoPS concentration (wt%); lattice parameter - C6AzoC4E4 (Å); y error; lattice parameter - C8AzoC8E4 (Å); y error. $$ \ $$ Fig4 contains the XY data for the UV-Vis absorption spectra of a dispersion of MO- C8AzoC8E4 (20 wt%)-water (10 wt%) diluted to 69 µM. Columns are: wavelength (nm) and absorbance on storage in the dark, irradiation at 365 nm, irradiation at 450 nm. $$ \ $$ Fig5a contains the raw SAXS XY data for dispersions containing MO-C8AzoC8E4-water (20wt%) on increasing C8AzoC8E4 concentration in the trans and cis states. Columns are q (Å-1) and intensity for: trans, 10 wt% C8AzoC8E4; trans, 20 wt% C8AzoC8E4; trans, 30 wt% C8AzoC8E4; cis, 10 wt% C8AzoC8E4; cis, 20 wt% C8AzoC8E4; cis, 30 wt% C8AzoC8E4. Fig5b contains the XY data for lattice parameter vs. initial water concentration for MO-AzoPS (10 wt%) -water dispersions in the trans and cis states. Columns are: initial water concentration (wt%); lattice parameter - trans, C6AzoC4E4 (Å); y error; lattice parameter - cis, C6AzoC4E4 (Å); y error; lattice parameter - trans, C8AzoC8E4 (Å); y error; lattice parameter - cis, C8AzoC8E4 (Å); y error. Fig5c contains the XY data for lattice parameter vs. AzoPS concentration for MO-AzoPS-water (20 wt%) dispersions in the trans and cis states. Columns are: AzoPS concentration (wt%); lattice parameter - trans, C6AzoC4E4 (Å); y error; lattice parameter - cis, C6AzoC4E4 (Å); y error; lattice parameter - trans, C8AzoC8E4 (Å); y error; lattice parameter - cis, C8AzoC8E4 (Å); y error. $$ \ $$ Fig6a contains contains the cryo-TEM micrograph for a dispersion of MO MO-C6AzoC4E4 (20 wt%)-water (20 wt%) in the cis state. The scale bar indicates 100 nm. Fig6b contains the cryo-TEM micrograph for a dispersion of MO-C8AzoC8E4 (20 wt%)-water (20 wt%) in the cis state. The scale bar indicates 100 nm. Fig6c contains the XY data for the hydrodynamic diameter (nm) and PDI vs. AzoPS concentration in MO- C6AzoC4E4-water (20wt%) dispersions in the trans and cis states. Columns are: AzoPS concentration (wt%); DH - trans; DH - cis; PDI - trans; PDI - cis; DH error - trans; PDI error - trans. $$ \ $$ Fig7a contains the XY data for the fluorescence spectra for a reference MO-water (20 wt%) dispersion and MO- C8AzoC8E4 (30 wt%)-water (20 wt%) dispersion, both loaded with Nile Red, before and after 3 min of UV irradiation. Columns are: wavelength (nm); intensity (reference, before UV); intensity (reference, after UV); intensity (C8AzoC8E4, before UV); intensity (C8AzoC8E4, after UV). Fig7b contains the data for emission intensity at 640 nm vs. time (minutes) after dispersion for a sample of MO- C8AzoC8E4 (30 wt%)-water (20 wt%) in the trans and cis states. Columns are: time, for trans (min); intensity, trans; time, for cis (min); intensity, cis. $$ \ $$ FigS1 contains POM micrographs for bulk LLC phases of MO and (a) 10 wt%, (b) 20 wt% and (c) 40 wt% water. FigS2 contains the raw SAXS XY data for the LLC phase formed from MO in excess water. Columns are q (Å-1) and intensity. FigS3 contains the example correlation data and cumulants fit plots used to calculate the Z-average hydrodynamic diameter and polydispersity index for a MO-C8AzoC8E4 (10 wt%)-water (10 wt%) dispersion. FigS4 contains photographs of LLC dispersions with varying initial water and AzoPS concentrations on storage in the dark for 10 months. FigS5 contains the cryo-TEM micrograph for a dispersion of MO-C8AzoC8E4 (10 wt%)-water (10 wt%) dispersion. The scale bar indicates 100 nm. FigS6 contains the raw SAXS XY data for dispersions of MO with varying initial water concentrations. Columns are q (Å-1) and intensity for: 10, 20, 30 and 40 wt% initial water. FigS7 contains the raw SAXS XY data for dispersions containing MO-C6AzoC4E4-water of varying concentration of C6AzoC4E4 and water. Columns are q (Å-1) and intensity for: 10 wt% water, 10 wt% C6AzoC4E4; 20 wt% water, 10 wt% C6AzoC4E4; 30 wt% water, 10 wt% C6AzoC4E4; 40 wt% water, 10 wt% C6AzoC4E4; 20 wt% water, 20 wt% C6AzoC4E4; 20 wt% water, 30 wt% C6AzoC4E4; 20 wt% water, 0 wt% C6AzoC4E4. FigS8a contains the XY data from the SAXS for plots of ln(I(q)) vs. q2 (Å-2) for dispersions of MO with varying initial water concentration. Columns are q2 (Å-2); ln(I(q)) for initial water concentrations of 10 wt%, y error, 20 wt%, y error, 30 wt%, y error, 40 wt%, y error. FigS8b contains the XY data from the SAXS for plots of ln(I(q)) vs. q2 (Å-2) for dispersions of MO-C6AzoC4E4-water (20 wt%) with varying C6AzoC4E4 concentration. Columns are q2 (Å-2); ln(I(q)) for C6AzoC4E4 concentrations of 10 wt%, y error, 20 wt%, y error, 30 wt%, y error. FigS9 contains the raw SAXS XY data for repeat dispersions containing MO-AzoPS (30 wt%)-water (20wt%). Columns are q (Å-1) and intensity for: C6AzoC4E4 repeats 1, 2 and 3; C8AzoC8E4 repeats 1, 2 and 3. FigS10a contains the raw SAXS XY data for dispersions containing MO- C6AzoC4E4 (30 wt%)-water (20wt%) at increasing temperatures. Columns are q (Å-1) and intensity for: 25, 35, 45 and 55 °C. FigS10b contains the raw SAXS XY data for dispersions containing MO- C8AzoC8E4 (30 wt%)-water (20wt%) at increasing temperatures. Columns are q (Å-1) and intensity for: 25, 35, 45, 55 °C and on cooling to 25 °C. FigS11a contains the XY data for the UV-Vis absorption spectra of C6AzoC4E4 in solution (57 µM); an MO-C6AzoC4E4 (20 wt%)-water (10 wt%) dispersion (69 µM); and, an MO-water (20 wt%) dispersion (46 µM). Columns are: wavelength (nm); absorbance for C6AzoC4E4 in dispersion; C6AzoC4E4 in solution; MO dispersion. FigS11b contains the XY data for the UV-Vis absorption spectra of C8AzoC8E4 in solution (68 µM); an MO-C8AzoC8E4 (20 wt%)-water (10 wt%) dispersion (69 µM); and, an MO-water (20 wt%) dispersion (46 µM). Columns are: wavelength (nm); absorbance for C8AzoC8E4 in dispersion; C8AzoC8E4 in solution; MO dispersion. FigS12 contains the XY data for the UV-Vis absorption spectra of a dispersion of MO- C6AzoC4E4 (20 wt%)-water (10 wt%) diluted to 69 µM. Columns are: wavelength (nm) and absorbance on storage in the dark, irradiation at 365 nm, irradiation at 450 nm. FigS13a contains the XY data for the UV-Vis absorption spectra of a dispersion of MO- C6AzoC4E4 (20 wt%)-water (10 wt%) diluted to 69 µM, as a function of time irradiated with UV (365 nm) light. Columns are: wavelength and absorbance at increasing time stamps (s). FingS13a_2 contains the XY data for UV irradiation time (s) vs. ln(A0-APSS)/(At-APSS) for a dispersion of MO- C6AzoC4E4 (20 wt%)-water (10 wt%) diluted to 69 µM. FigS13b contains the XY data for the UV-Vis absorption spectra of a dispersion of MO- C6AzoC4E4 (20 wt%)-water (10 wt%) diluted to 69 µM, as a function of time irradiated with blue (450 nm) light after 5 minutes of initial UV irradiation. Columns are: wavelength and absorbance at increasing time stamps (s). FigS13b_2 contains the XY data for blue irradiation time (s) vs. ln(A0-APSS)/(At-APSS) for a dispersion of MO- C6AzoC4E4 (20 wt%)-water (10 wt%) diluted to 69 µM. FigS14a contains the XY data for the UV-Vis absorption spectra of a dispersion of MO- C8AzoC8E4 (20 wt%)-water (10 wt%) diluted to 69 µM, as a function of time irradiated with UV (365 nm) light. Columns are: wavelength and absorbance at increasing time stamps (s). FigS14a_2 contains the XY data for UV irradiation time (s) vs. ln(A0-APSS)/(At-APSS) for a dispersion of MO- C8AzoC8E4 (20 wt%)-water (10 wt%) diluted to 69 µM. FigS14b contains the XY data for the UV-Vis absorption spectra of a dispersion of MO- C8AzoC8E4 (20 wt%)-water (10 wt%) diluted to 69 µM, as a function of time irradiated with blue (450 nm) light. Columns are: wavelength and absorbance at increasing time stamps (s). FigS14b_2 contains the XY data for blue irradiation time (s) vs. ln(A0-APSS)/(At-APSS) for a dispersion of MO- C8AzoC8E4 (20 wt%)-water (10 wt%) diluted to 69 µM. FigS15 contains the XY data for the UV-Vis absorption spectra of a dispersion of MO- C6AzoC4E4 (20 wt%)-water (10 wt%) as a function of time stored in the dark after 5 minutes of initial UV irradiation. Columns are: wavelength (nm), absorbance in the native, trans state and at increasing time stamps after UV irradiation (days). FigS15_2 contains the XY data for time stored in the dark (s) vs. ln(A0-APSS)/(At-APSS) for a dispersion of MO- C6AzoC4E4 (20 wt%)-water (10 wt%) diluted to 69 µM. FigS16 contains the XY data for the UV-Vis absorption spectra of a dispersion of MO- C8AzoC8E4 (20 wt%)-water (10 wt%) as a function of time stored in the dark after 5 minutes of initial UV irradiation. Columns are: wavelength (nm), absorbance in the native, trans state and at increasing time stamps after UV irradiation (days). FigS16_2 contains the XY data for time stored in the dark (s) vs. ln(A0-APSS)/(At-APSS) for a dispersion of MO- C8AzoC8E4 (20 wt%)-water (10 wt%) diluted to 69 µM. FigS17 contains the raw XY SAXS data for dispersions of MO- C6AzoC4E4 (10 wt%)-water with increasing concentration of initial water in the trans and cis states. Columns are: q (Å-1) and intensity for: trans, 10 wt%; trans, 20 wt%; trans, 30 wt%; trans, 40 wt%; cis, 10 wt%: cis, 20 wt%: cis, 30 wt%: cis, 40 wt%. FigS18 contains the raw XY SAXS data for dispersions of MO- C6AzoC4E4- water (20 wt%) with increasing concentration of C6AzoC4E4 in the trans and cis states. Columns are: q (Å-1) and intensity for: trans, 10 wt%; trans, 20 wt%; trans, 30 wt%; cis, 10 wt%: cis, 20 wt%: cis, 30 wt%. FigS19 contains the raw XY SAXS data for dispersions of MO- C8AzoC8E4 (10 wt%)-water with increasing concentration of initial water in the trans and cis states. Columns are: q (Å-1) and intensity for: trans, 10 wt%; trans, 20 wt%; trans, 30 wt%; trans, 40 wt%; cis, 10 wt%: cis, 20 wt%: cis, 30 wt%: cis, 40 wt%. FigS20 contains the raw SAXS XY data for repeat dispersions containing MO-AzoPS (30 wt%)-water (20wt%) in the cis state. Columns are q (Å-1) and intensity for: C6AzoC4E4 repeats 1, 2 and 3; C8AzoC8E4 repeats 1, 2 and 3. Text files can be opened with any text editor. PNG or JPEG or TIFF files can be opened with any imaging editor 
Type Of Material Database/Collection of data 
Year Produced 2023 
Provided To Others? Yes  
Impact The data here was used to publish a paper entitled "Light-Responsive Molecular Release from Cubosomes Using Swell-Squeeze Lattice Control" in the Journal of the American Chemical Society. 
URL https://www.repository.cam.ac.uk/handle/1810/345670
 
Description Tour guide at Diamond Light Source for groups of school and university students 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact Multiple tours in groups of 6 were given to school students, university undergraduates and postgraduates. The tours raised questions from the audience, who gained more awareness of the research carried out at the Diamond Light Source, and what a career in research entails.
Year(s) Of Engagement Activity 2022