Gelation behaviour and gel properties of two-component organogels containing a photoresponsive gelator

Abstract

Herein, we report the gelation behaviour and gel properties of two-component organogels consisting of 1,4-bis[(3,4-bisoctyloxyphenyl) hydrozide] phenylene (BPH-8) and a photoresponsive gelator 4-[3,5-(bisoctyloxyphenyl)]-9-anthracene formyl hydrazine (MB8). It was demonstrated that the mixture of BPH-8 and MB8 showed self-sorted aggregation behaviour in ethanol. A gradient cooling procedure was used to obtain self-sorted gels of BPH-8 and MB8. Kinetics of gelation of the two component gels showed that D_f values of MB8 fibers decreased due to the presence of BPH-8 gel. The two-component gels showed visible light (λ_{visible light} = 350–570 nm) induced gel–gel transitions due to the orthogonal self-assembly of two gelators through the trans–cis conformation transition of –CN– bond of MB8 component. In addition, the stable patterned two-component gel was achieved using a special shape mask, which enabled the gels to be irradiated by visible light in a particular area. The irradiated gels showed weak emission, reduced storage modulus, a shorter linear viscoelastic region, and higher wetting angle compared to that unirradiated region due to the collapse of the MB8 aggregates under visible light.