Stimuli-responsive liquid crystal elastomer microparticles

Abstract

This thesis centres on the creation of nematic and chiral nematic polymer and elastomer microparticles, with defined confinement textures due to surface anchoring from the host solvent, using a series of novel nematic and chiral nematic monomers. Droplets were produced using a homemade microfluidic technique and photo-polymerised into particles, followed by an analysis of the responsive properties. The synthesis of nematic and chiral nematic monomers, polymers and elastomers, as well as the characterisation of their thermal and optical properties is presented. Chiral nematic mixtures were polymerised into thin-films capable of visible selective reflection and which experience a pitch contraction upon removal of a chiral dopant. The design and development of a microfluidic chip to create monodisperse droplets is discussed. The droplets were photopolymerised by two methods into elastomer particles and the reversible shape change responses to temperature were analysed. Monodisperse chiral nematic droplets and particles were made, using the monomer mixtures established together with the microfluidic technique developed, and concluded with an investigation of the responsiveness of the particles to external stimuli.