Reaction-Induced Phase Separation: A Strategy to Synthesize Azobenzene-Modified All-Optical PDLC Devices

A. B. OROFINO; P.A. OYANGUREN; M. J. GALANTE

MACROMOLECULAR CHEMISTRY AND PHYSICS

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2018 vol. 219 p. 1700626 - 1700631

1022-1352

This work presents the synthesis of all-optical polymer dispersed liquidcrystals (PDLC) devices, in which the reversible trans?cis photoisomerizationof azobenzene groups is used to induce the transition in the liquidcrystal (LC) phase, activating the film from an opaque to a translucent state.The appropriate morphology is obtained through a reaction-induced phaseseparation strategy using an epoxy?amine matrix modified with azobenzeneprecursors and the addition of a thermoplastic polymer (polystyrene, PS),which promotes the phase separation and the preferential location of the LCin separated domains. Formulations with liquid crystal content of 50 wt%,5 wt% of modifier (PS), and 10 wt% of azo-precursor present a reversibleon?off optical response when irradiating the sample with the activation beamat λ = 488 nm. It is demonstrated that the liquid crystal responds accordingto the expected cooperative movement of orientation with the azobenzenegroups. Based on the study of the PDLC devices obtained, its potentialtechnological application can be confirmed.