Photo-cleaving and photo-linking: Applications for polymer networks and self-assemblies

Olivia McNair, Craig Machado, Daniel Savin

University of Southern Mississippi. University of Florida

This talk will present work in the use of photochemistry in two different contexts. First, photocleavable linkages, such as those based on 2-nitrobenzyl alcohol, provide a convenient handle for photo-responsiveness. We have explored the self-assembly of block copolymers where the hydrophobic core block contains the photocleavable unit. In this design, the hydrophobic core block remains hydrophobic after cleavage, but the substantial change in the hydrophobic/hydrophilic balance results in a morphology change (e.g.: from vesicle to micelle) over time. These assemblies were characterized using static and dynamic light scattering, as well as electron microscopy.  The second part of this talk will focus on advances in photolinking “thiol-ene” chemistry to produce functional thermoset networks.  Here, molecular-level modifications can impart additional function and improve overall macroscopic properties of these novel materials. We present some recent work where we incorporate azobenzene moieties into the polymer network.