Viscoelastic and Photoresponsive Properties of Microparticle/Liquid-Crystal Composite Gels: Tunable Mechanical Strength along with Rapid-Recovery Nature and Photochemical Surface Healing using an Azobenzene Dopant

摘要

We investigated viscoelastic and photoresponsivenproperties of the microparticle/liquid-crystal (LC)ncomposite gels. The mechanical strength of the colloidal gelsncan be widely tuned by varying particle concentrations. Withnincreasing particle concentration, a storage modulus of thenparticle/LC composite gels increased and reached over 104 Pa,nshowing good self-supporting ability. We demonstrated for thenfirst time that the particle/LC composite gels exhibited rapidnand repetitive recovery of the mechanical strength after largeamplitudenoscillatory breakdown. In addition, photoresponsivenproperties of the composite gels were investigated by the cis−trans photoisomerization of the azobenzene compound doped intonthe host LCs. The photochemical gel−sol transition could be repeatedly induced by changing the phase structure of the host LCsnbetween nematic and isotropic, using the photoisomerization. The particle/LC composite gels can be applied to opticallynhealable materials by the site-selective gel−sol transition based on the photochemical modulation of the phase structures of thenhost LCs.