2022

Results dissemination in national/international conferences:

• Polypropylenedioxythiophene-based electrodes for energy storage smart window applications
  M. D. Damaceanu, A. P. Chiriac
  7th European Symposium of Photopolymer Science (ESPS 2022), Istanbul - TURKEY, September 19-22, 2022 (oral presentation) 

• Polimeri pe baza de propilendioxitiofen cu caracteristici electrocrome si capacitive
  A. P. Chiriac, M. D. Damaceanu
  A XXXVI-a Conferinta Nationala de Chimie, Călimăneşti – Căciulata, Vâlcea, 04 - 07 Octombrie 2022 (prezentare orala)

• Energy-related polymer materials: from electrochromic to energy storage applications
  M. D. Damaceanu, C. P. Constantin
  3-day International Conference on Materials Science (3d-ICOMAS), Verona - ITALY, October 26-28, 2022  (invited lecture)

A sumary of the main results obtained during project implementation in 2022 is presented below.

The EnStoreSW project aims at developing polymers based on thiophene derivatives for use both as capacitive and electrochromic materials, as well as their interdisciplinary investigation and testing in flexible energy storage smart windows, so as to reach TRL 4. For this purpose, in Stage 1 (year 2022) the synthesis of monomers and polymers based on ProDOT was carried out, with emphasis on the synthetic processes optimization and purification methods, as well as on their structural identification and physico-chemical investigation as isolated molecules (in solution). Thus, 3 monomers based on ProDOT with different substituents (type alkyl, ester or hydroxyl) were synthesized through different techniques that required the optimization of the experimental conditions. The monomers were purified by column chromatography and structurally characterized by spectral methods, such as FTIR, 1H and 13C-NMR, which confirmed their correct structure. Also, they were studied by UV-Vis absorption and fluorescence spectroscopy, with the aim to evaluate the main electronic transitions that occur in these monomers, but also the changes induced on the electronic transitions by the different anchored side substituents. Based on these monomers and a commercial monomer, 8 polymers based on ProDOT were obtained. The synthesis of polymers was carried out by different methods, such as electrochemical polymerization, oxidative polymerization, direct C-H arylation and Yamazaki-Higashi polycondensation. After optimizing the synthesis conditions, the polymers were isolated from the reaction medium and purified by specific methods, then confirmed from the structural point of view by FTIR, 1H and 13C-NMR spectroscopy, while their molecular weights were evaluated by gel permeation chromatography. The photo-optical behavior of the polymers was investigated by UV-Vis absorption and fluorescence spectra recorded in solution. These highlighted the presence of a main absorption band at wavelengths beyond 450 nm, with the exception of one polymer, which, due to a reduced conjugation, dispalyed a weak absorption at approximately 360 nm. By excitation with the wavelength corresponding to the main absorption maximum, all polymers showed fluorescence, with emission in the blue, yellow or orange-red spectral range, according to the structure of each polymer. All polymers showed oxidation processes in the cyclic voltammetry measurements, of reversible or irreversible character, depending on the structure of the monomeric unit. DFT molecular simulations showed that the polymers have planar, conjugated structures, with molecular orbitals delocalized mainly on the thiophene ring, excepting the polymer obtained by polycondensation, which has a twisted conformation and well-separated molecular orbitals. The simulation of the oxidized species (polarons/bipolarons) generation led to absorption spectra with new bands, which indicated that the present polymers have potential as electrochromic materials. The obtained results were analyzed and discussed in the stage report, and part of them were disseminated at 3 scientific events in the form of 2 oral communications and 1 invited lecture.