The Role of Crosslinker Molecular Structure on Mechanical and Light-Actuation Properties in Liquid Crystalline Networks.

Phase behavior modulation of liquid crystalline molecules can be addressed by structural modification at molecular level. Starting from a rigid rod-like core -, e.g., composed by aromatic rings - reduction of the symmetry or increase of the steric hindrance by different substituents generally reduces the clearing temperature. Similar approaches can be explored to modulate the properties of Liquid Crystalline Networks (LCNs)- shape-changing materials employed as actuators in many fields. Depending on the application, the polymeric properties have to be adjusted in terms of force developed under stimuli, kinetics of actuation, elasticity, and resistance to specific loads. In this paper, we explore the crosslinker modification at the molecular level and its effect on photoresponsive LCNs prepared by acrylate photopolymerization, towards the optimization of their properties, and the development of light-responsive artificial muscles. The synthesis and characterization of photopolymerizable crosslinkers, bearing different lateral groups on the aromatic core is reported. Such molecules were demonstrated able to strongly modulate the material mechanical properties, such as kinetics and maximum tension under light actuation, opening up to interesting materials for biomedical applications. This article is protected by copyright. All rights reserved.