Photoactuating liquid crystalline elastomers (LCE) are promising candidates for an application as artificial muscles in microdevices. In this work, we demonstrate that by optimizing (1) the illumination conditions and (2) the mixture of azo monomer and azo crosslinker, thick films of an all-azo LCE can be prepared, which show a strong length change without bending during photoactuation. This becomes possible by working with white light (about 440 nm), whose absorption is low, leading to a large penetration depth. By adding an azo crosslinker to a previously prepared system, several improvements of the actuation properties-like a stronger photoactuation at lower operational temperatures-could be achieved. In addition, films of different crosslinker concentrations and thicknesses were produced by photopolymerization at varying temperatures within a magnetic field, and their thermo-and photoresponsive behavior was investigated. An extraordinarily strong maximal thermal actuation of 46% and-by exposure to white light at 70 • C-a photoresponsive change in length of up to 40% in just about 13 s could be obtained. Even densely crosslinked samples were still able to photoactuate remarkably. Isothermal back-deformation could either be achieved by irradiation with red light (7 min) or by keeping the film in the dark (13 min).

Capitalizing on the inertness of styrene toward Grignard reagents, 4-vinylphenyl­magnesium bromide was utilized for the rapid and convenient preparation of the protected monomer 2,2-dimethyl-4-(4-vinylbenzyl)-1,3-dioxolane (DMVBDO), avoiding the use of catalysts and painstaking purification protocols. Well-defined homopolymers, statistical copolymers, and block copolymers with styrene (S) as a comonomer were prepared in THF at −78 °C via carbanionic living polymerization. The overall molecular weights ranged from 4.5 to 68.9 kg mol–1 with low dispersities (Đ 1.04–1.15). Copolymers were synthesized with styrene feed ratios (X feed) from 15 to 95 mol % with glass transition temperatures (T g) between 46 and 91 °C. Whereas polystyryllithium served as an excellent macroinitiator for the preparation of the block copolymer PS0.5-b-P­(DMVBDO)0.5, the inverse block order, i.e., synthesis of P­(DMVBDO)0.5-b-PS0.5, yielded a bimodal molecular weight distribution (MWD) with increased dispersity, which is ascribed to slow crossover. Rapid deprotection of both homo- and copolymers to release two hydroxyl groups per DMVBDO unit was achieved via acidic hydrolysis. The deprotected block copolymer PS0.5-b-P­(VPPDO)0.5 showed phase separation, indicated by two T g values (68 and 86 °C). Homogeneous brush copolymers of the type P­(S85-co-VPPDO5)-g-PLLA and P­(S85-co-VPPDO6)-g-PEO were demonstrated by using quantitative “grafting from” with l-lactide and ethylene oxide, respectively. The brush-like copolymers were obtained in quantitative yields while maintaining monodisperse MWD.