Unexpected Polymer Degradation Mechanisms

Next generation polymer-based applications ranging from flexible microelectronics to drug delivery systems require specific and tunable material properties.

Desired material properties are obtained by controlling the molecular weight characteristics, molecular architecture and composition of the polymers themselves. For example, block copolymers which contain two chemically distinct polymers gives rise to a final material with a combination of properties originating from both independent blocks. Unlike a simple blend of polymers, block copolymers are covalently bound and therefore do not macro phase separate. In fact, block copolymers do phase separate - but only on the nanoscale. This thermodynamically predictable self-assembly gives rise to specialized applications such as nano-porous membranes, polymer templates for nano metallic rods and high surface catalytic supports, to name but a few examples.

Nitroxide mediated polymerization (NMP) is an industrially friendly technique which often only requires a simple unimolecular initiator to obtain polymers with low molecular weight distributions and high chain end livingness: factors which are necessary to obtain well defined block copolymers. NMP is versatile; it can be performed in aqueous systems, results in polymers that are biologically benign, is used to grow polymers off of inorganic surfaces, and can synthesize polymers for electronic applications without any specialized purification required. Over the years, researchers have been finding ways to use NMP to polymerize a variety of functional monomers including styrenics, acrylates, acrylamides and even methacrylates.

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