Well-Defined Polymers for Nonchemistry Laboratories using Oxygen Tolerant Controlled Radical Polymerization

We present the use of an oxygen tolerant controlled radical polymerization (photoinduced electron/energy transfer-reversible addition fragmentation chain transfer polymerization, PET-RAFT) as a simple method for preparing controlled radical polymers in an undergraduate laboratory. Unlike conventional techniques, PET-RAFT polymerizations require no deoxygenation, heating, or special equipment. This removes hazards and complexity from the experimental setup, as well as sources of error and variability in the polymers produced. In this program, students used PET-RAFT to synthesize poly(N-isopropylacrylamide) coated gold nanoparticles and studied the effect of the polymer on the size, optical properties, and aggregation state of the nanoparticles in response to temperature. In parallel, students used PET-RAFT to study the chemistry of radical copolymerization by measuring the reactivity ratios of a range of vinylic monomers. Both experiments would be very difficult to perform in an undergraduate laboratory by conventional controlled radical polymerization techniques. The PET-RAFT technique we present can be used to prepare well-defined polymers easily for any number of applications beyond this, particularly in materials, biology, engineering, and physics laboratories that are not set up for complicated polymer synthesis.