(268e) Single-Step Synthesis of Shaped Polymeric Particles Via Initiated Chemical Vapor Deposition By Leveraging Liquid Crystals As a Reaction Medium and Real-Time Display

Shaped polymer particles will benefit a wide range of applications such as targeted drug delivery vehicles and in soft robotics with reconfigurable super assemblies and directed motion, but existing synthesis approaches are commonly multistep and limited to a narrow size/shape range. In this study, liquid crystals (LCs) were leveraged both as a reaction medium and as a real-time display of the polymerization conditions and progression, by setting up a custom in-situ long-focal range microscope assembly. Tapping into the anisotropy in molecular alignments of nematic liquid crystals (LCs), we developed a novel single-step technique for polymerizing divinylbenzene (DVB) via initiated chemical vapor deposition (iCVD) to generate a variety of shapes including nanospheres, hemispherical micro-domes, orientation-controlled microgels, microspheres, spheroids, and micro-discs. In-situ monitoring coupled with iCVD allowed for precisely optimized and continuous delivery of vapor-phase reactants, thus avoiding disruption of the LC structure, a critical limitation in past LC-templated polymerization. In addition, by implementing cross polarized microscopy characterization in real-time, we unraveled the role LC-substrate interface played in the formation of shaped particles. Detailed image analysis and chemical composition characterization revealed key mechanistic insights of shape and size controlled polymer synthesis in LC. By harnessing LC display output as signal amplifiers for monitoring reaction microenvironment in real-time in this study, we lay the foundation for agile development of next generation particle synthesis technologies, to be further employed in tandem with data-driven approaches.