Radical mediated thiol-ene/yne dispersion polymerizations

Abstract

We report the synthesis of polymeric particles using radical mediated step-growth thiolene and thiol-yne "click" dispersion polymerizations in alcoholic solvents. Various alkene, alkyne and thiol monomers were used, and thermal, photo-or redox initiation methods were all shown to be effective means to initiate polymerization. Polymer particles typically were formed with diameters in the range of several hundred nanometers, with narrow size distributions though broader than typical free-radical chain-growth dispersion polymerizations. Photoinitiation yielded the smallest sizes due to the rapid nucleation of particles as compared to redox and thermal initiation methods. Reaction kinetics were monitored by FT-IR spectroscopy for aliquot samples taken at various reaction durations. The reaction achieved full conversion in

Site‐Specific Surface Functionalization via Microchannel Cantilever Spotting (µCS): Comparison between Azide–Alkyne and Thiol–Alkyne Click Chemistry Reactions

“…Addition of a single thiol to a cycloalkyne is relatively rapid and this reaction can be performed spontaneously even in the absence of light and photoinitiator in an unpurged atmosphere. Cyclooctynes used for SPAAC (shown in Figure S1 in the Supporting Information) can be usable for doing click reaction with thiol as well …”

Composite Particles From Pickering‐Stabilized Radical Mediated Thiol‐Ene Suspension Polymerizations

“…Previously, we and others developed radical‐mediated thiol‐ene and thiol‐yne polymerizations for the production of colloidal polymer particles . Synthesis of colloidal polymers have been shown to work in different dispersed polymerization modes, such as emulsions, dispersions, miniemulsions and suspensions . In these prior cases, the particles were emulsified or stabilized using common surfactants, such as sodium dodecyl sulfate (SDS), or natural gums .…”

TEMPO Driven Mild and Modular Route to Functionalized Microparticles

“…Tyson et al reported thiol‐ene reactions initiated by visible light in presence of a transition metal polypyridyl photocatalyst and p ‐toluidine as an additive. Critically, thiol‐ene chemistry is widely used for a variety of applications such as the synthesis of crosslinked functional polymeric microspheres as well as the functionalization of microspheres . Dispersion polymerization based on thiol‐ene/thiol‐yne chemistry features some characteristics associated with the “click” principle, i.e., high reactivity with monomers, excellent yields, selectivity, and reaction orthogonality .…”

“…Recently, Bowman and co‐workers synthesized photoresponsive polymeric particles by photoinduced nitrile imine‐mediated tetrazole‐ene cycloaddition (NITEC) and thiol‐Michael addition dispersion polymerization in which the polymeric particles feature an inherent tetrazole‐ene functionality for postparticle formation chemistry. Alimohammadi et al synthesized polymeric particles by thiol‐ene and thiol‐yne free radical dispersion polymerization studying the effect of initiator (photo, thermal, and redox) on the particle size. Durham et al synthesized polymeric microspheres using thiol‐ene/thiol‐yne suspension polymerization in presence of thermal and photoinitiator, while Tan et al developed porous polymer particles using water born thiol‐ene suspension polymerization and studied the effect of polymerization conditions and porogen amounts on the morphology of particles and their sizes.…”