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oai:figshare.com:article/34034013 2026-09-30T16:26:57Z category_1 category_4 category_915 category_7 category_21 category_873 category_39 portal_63 item_type_6 month_year_09_2026

Alkylthieno[2,3‑d][1,3]thiazole as a Dual-Mode Design Principle for Single-Beam Unidirectional Spontaneous Surface-Relief Gratings in Push–Pull Azobenzenes Yevhenii Prykhodko (25144890) Shahla Golghasemi Sorkhabi (25144893) Elif Goktepe (25144896) Romuald Herbinet (17592540) Sonia Zielinska (21391096) Ewelina Ortyl (21391099) Aleksandra Korbut (11792530) Matthieu Loumaigne (2010475) Regis Barille (10839474) Cyprien Lemouchi (1455784) Biophysics Biochemistry Physical Sciences not elsewhere classified Medicine Biotechnology Chemical Sciences not elsewhere classified Ecology tuning operates independently spontaneously form surface polymethacrylate azobenzene homo mode design principle induced mass transport e ., methyl alkyl substituent bulkiness 75 ° c maximum absorption wavelength covalently bonded systems 3 ‑< italic srg directional spread g </ sub abs </ sub copolymers (< b ttz </ b p2c </ b beam unidirectional sp thiazole (< b max </ sub covalently bonded shifted absorption beam irradiation n </ >< sub beam sp thf ), systematic modulation reversible photoisomerization responsive applications relief gratings polymer ’ order parameter optimized copolymer heterocycle provides general strategy film spin electronic structure developing next Pseudostilbene (<b>PS</b>) azobenzene-functionalized polymethacrylate (<b>PMAzo</b>) films are known to spontaneously form surface-relief gratings (SP-SRGs) under single-beam irradiation, driven by reversible photoisomerization-induced mass transport. Yet achieving macroscopic single-beam unidirectional SP-SRG in covalently bonded systems with a value of maximum absorption wavelength (λ_absmax) above 500 nm remains elusive due to the trade-off between red-shifted absorption and chain mobility. Here, the alkylthieno[2,3-<i>d</i>][1,3]thiazole (<b>TTz</b>) heterocycle resolves this trade-off through a dual-mode design principle: its electron-withdrawing nature extends absorption range from 400 to 650 nm and the value of λ_absmax to 536 nm (film spin-coated from THF), while systematic modulation of alkyl substituent bulkiness (i.e., methyl, <i>n</i>-butyl, 2-ethylhexyl) on <b>TTz</b> simultaneously controls chromophore aggregation and decreases the polymer’s glass transition temperature (<i>T</i>_g) from 144 to 75 °C. A family of polymethacrylate azobenzene homo- and copolymers (<b>PMAzo-TTz</b>, <b>P1a-P4c</b>) was synthesized and characterized, demonstrating that this <i>T</i>_g tuning operates independently of the chromophore’s electronic structure, a key feature enabling decoupled material optimization. As a result, the optimized copolymer <b>P2c</b> (<i>T</i>_g = 94 °C), spin-coated from DCM, exhibits reduced chromophore aggregation (λ_abs_max = 505 nm) and achieves, to the best of our knowledge, the first highly ordered unidirectional single-beam SP-SRG in a covalently bonded <b>PS–PMAzo</b> system absorbing beyond 500 nm (periodicity 380–400 nm, amplitude ∼12 nm, order parameter S = 0.73, corresponding to SP-SRG directional spread of 22.9°). This work establishes clear structure-property relationships linking chromophore aggregation, <i>T</i>_g behavior, and light-induced mass transport. The dual-mode design principle of the <b>TTz</b> heterocycle provides a general strategy for developing next-generation red-shifted optomechanically active polymers for photonic and light-responsive applications. 2026-09-30T00:00:00Z Text Journal contribution 10.1021/acsapm.6c02633.s001 https://figshare.com/articles/journal_contribution/Alkylthieno_2_3_d_1_3_thiazole_as_a_Dual-Mode_Design_Principle_for_Single-Beam_Unidirectional_Spontaneous_Surface-Relief_Gratings_in_Push_Pull_Azobenzenes/34034013 CC BY-NC 4.0