The self-assembly of monomeric and polymeric building blocks has long provided a route to the formation of materials with complex and functional architectures and responses. Within this subset of materials chemistry, the preparation of liquid crystalline elastomers (LCEs, T<sub>g</sub> &lt; r.t.) and networks (LCNs, T<sub>g</sub> &gt; r.t.) has been prolific due to the programmability of the long-range order achieved in their self-assembled liquid crystalline phases. Disruptions in this order are translated across the entirety of a polymeric monolith resulting in macroscopic shape change. Though disruptions in order may be triggered by a variety of external stimuli, the salient features of a light-activated process provide increased control over the subsequent deformation. Recently, advances in the design of photoresponsive chromophores has enabled the preparation of liquid crystalline materials displaying stable, light-activated shape-change. Herein, we describe the preparation of photoresponsive azobenzene-functionalized LCEs capable of undergoing large scale, macroscopic deformations. Through the inclusion of a functionalized-azobenzene displaying a long-lived cis-isomer, persistent (&gt;72 hrs), all-optical control of shape deformation and restoration was achieved. The directed self-assembly of the liquid crystalline monomers affords precise control over the macroscopic architecture, and consequently photoresponsive origami patterns were achieved. By careful investigation of the kinetics of the photoisomerization process and the macroscopic shape relaxation, the influence of the polymer chain dynamics was optimized and enhanced via the inclusion of stabilizing, covalent-adaptable linkages.

Exploiting self-assembly in photoresponsive materials

2019 Fall National Meeting

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