Cholesteric Polymer Scaffolds Filled with Azobenzene-Containing Nematic Mixture with Phototunable Optical Properties

The past two decades witnessed tremendous progress in the field of creation of different types of responsive materials. Cholesteric polymer networks present a very promising class of smart materials due to the combination of the unique optical properties of cholesteric mesophase and high mechanical properties of polymer networks. In the present work we demonstrate the possibility of fast and reversible photocontrol of the optical properties of cholesteric polymer networks. Several cholesteric photopolymerizable mixtures are prepared, and porous cholesteric network films with different helix pitches are produced by polymerization of these mixtures. An effective and simple method of the introduction of photochromic azobenzene-containing nematic mixture capable of isothermal photoinducing the nematic–isotropic phase transition into the porous polymer matrix is developed. It is found that cross-linking density and degree of polymer network filling with a photochromic nematic mixture strongly influence the pho...