p-Methoxy Azobenzene Terpolymer as a Promising Energy-Storage Liquid Crystal System

Ibrahim, A. Ramadan and Khyasudeen, M. Faisal and Husband, John and Alauddin, Sakinah Mohd and Aripin, Nurul Fadhilah Kamalul and Velayutham, Thamil Selvi and Martinez-Felipe, Alfonso and Abou-Zied, Osama K. (2021) p-Methoxy Azobenzene Terpolymer as a Promising Energy-Storage Liquid Crystal System. Journal of Physical Chemistry C, 125 (41). pp. 22472-22482. ISSN 1932-7447, DOI https://doi.org/10.1021/acs.jpcc.1c07081.

Full text not available from this repository.


Light-responsive materials capable of undergoing photoinduced molecular transformation are excellent candidates for energy storage. Herein, we report a promising new liquid crystalline terpolymer that is capable of trapping the absorbed photon energy upon exposure to UV light through trans -> cis isomerization and molecular aggregation. MeOAzB-T (contains pmethoxyazobenzene, 2- acrylamido- 2-methyl-1-propanesulfonic acid, and methyl(methacrylate) monomeric units) shows a trans. cis normal thermal recovery in solution (THF) after UV exposure, whereas in the glassy state (at 22 degrees C) and smectic phase (at 75 degrees C), the recovery process indicates an unusual increase in absorbance of the trans isomer. Surprisingly, when the smectic phase was cooled down to the glassy state while maintaining UV exposure, the increase in absorbance of the trans isomer was maintained at the same level in the dark (monitored for 20 days) until the sample was heated to 75 degrees C and then cooled to 22 degrees C in which a full recovery was achieved. Enhancement of H- and Jaggregations of the trans-MeOAzB units was found to be responsible for the absorbance increase. Both forms of aggregation have absorbance signatures and were reproduced by time-dependent density functional theory (TD-DFT). A long lifetime component was detected in the femtosecond transient absorption (TA) spectra in thin films (215 ps in the glass state and 97 ps in the smectic phase) and was assigned to a long-lived intermediate state as a result of aggregation. The stability of the excited state leads to more aggregation as a consequence of the larger dipole moment, compared to the ground state, which is manifested in the TD-DFT calculations as an increase in electron density at the central azo bond. The current results suggest that aggregation after UV irradiation can be maintained for a long time at room temperature and can be relaxed to the original configuration by heating above the glass transition, showing the suitability of MeOAzB-T as a solar thermal fuel.

Item Type: Article
Funders: Sultan Qaboos University, His Majesty's Trust Fund for Strategic Research [Grant No: SR/SCI/CHEM/18/01 & IG/SCI/CHEM/21/03], Malaysian Ministry of Higher Education [Grant No: 600-IRMI/FRGS 5/3 (374/2019)], Carnegie Trust for the Universities of Scotland [Grant No: RIG008586], Royal Society of London European Commission [Grant No: RGS\R1\201397], Royal Society of London [Grant No: M19-0000], Royal Society of Edinburgh, Scottish Government
Uncontrolled Keywords: Energy storage; Liquid crystalline terpolymer; Solar thermal fuel
Subjects: Q Science > Q Science (General)
Q Science > QD Chemistry
T Technology > T Technology (General)
Divisions: Faculty of Science
Depositing User: Ms Zaharah Ramly
Date Deposited: 29 Jun 2022 06:36
Last Modified: 29 Jun 2022 06:36
URI: http://eprints.um.edu.my/id/eprint/33989

Actions (login required)

View Item View Item