The transfer and amplification of cyanostilbene molecular function to advanced flexible optical paints through self-crosslinkable side-chain liquid crystal polysiloxanes

Abstract

A self-crosslinkable side-chain liquid crystal polysiloxane containing cyanostilbene (Si–CSM) was newly synthesized for the development of a new generation of flexible optical paints. The photoisomerization of the cyanostilbene moiety at the molecular level was transferred and amplified to the phase transition of Si–CSM, resulting in changes in the macroscopic optical properties of the Si–CSM thin film. The self-crosslinking reaction between Si–H groups in the Si–CSM polymer backbone caused the self-crosslinked Si–CSM thin film to be very elastic and both thermally and chemically stable. Therefore, the self-crosslinked Si–CSM thin film endured stretching and bending deformations under relatively harsh conditions. In addition, the uniaxially oriented and self-crosslinked Si–CSM thin film generated linearly polarized light emission. Polarization-dependent and photopatternable secret coatings were fabricated via a spontaneous self-crosslinking reaction after coating the Si–CSM paint and irradiating ultraviolet (UV) light through a photomask. This newly developed flexible optical Si–CSM paint can be applied in next-generation optical coatings.