Liquid crystal elastomers (LCE) are loosely crosslinked, anisotropic polymer networks that can exhibit exceptionally large and potentially useful shape changes with applied stimuli. Recent reports have detailed the ability to locally orient the director profile within LCEs and “program” the material for a desired applications, i.e. actuators, dampeners, or sensors. Here, we will detail our efforts in making and improving upon chemistry formulations that are conducive to LCE photoalignment orientation methods. Specifically, we employ a so called “click” reaction between thiols and alkenes to prepare programmable LCEs. A major advantage of the thiol-ene reaction is the ease at which it can proceed: either via radical addition to olefins or through anionic addition to α,β-unsaturated carbonyl compounds. Herein, we explore new thiol-ene formulations targeted at generating more robust LCEs by systematically varying the chain length of the reactive mesogens and the nature of the dithiols employed. The solventless, photochemical methods employed here allows for easy film generation, and improvements to the LCEs strength, toughness, and elasticity based on the change in substituents and polymerization method used will be discussed.

Facile synthesis of robust, photopolymerizable liquid crystal elastomers

253rd National Meeting (2017)

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