RAFT polymerisation to form stimuli-responsive polymers
Stimuli-responsive polymers adapt to their surrounding environment. These polymers are capable of responding to a variety of external stimuli, which include optical, electrical, thermal, mechanical, redox, pH, chemical, environmental and biological signals. They are encountered in many environments. They can have a variety of architectures (e.g., copolymers, blocks, stars). They may be present as isolated macromolecules in a medium, as supramolecular assemblies, as smart coatings, as networks or some combination of these possibilities.
A new paper is concerned with the process of forming such polymers by radical polymerisation with reversible addition fragmentation chain transfer (RAFT). RAFT polymerisation has an advantage over most processes for reversible deactivation radical polymerisation (RDRP) in its tolerance of a wide range of unprotected functionalities. Three basic strategies for forming stimuli-responsive polymers are considered: RAFT polymerisation of functional monomers (a “grafting through” approach), the post-polymerisation modification of RAFT-synthesised polymers (some combination of “grafting through”, “from” and “to”), and the use of functional RAFT agents and RAFT end-group transformation (often “grafting from”).
Combination with other processes
Other syntheses involve combinations of these processes and of RAFT polymerisation with other processes. The scientists also consider the responsiveness of the thiocarbonylthio-functionality of macroRAFT agents in terms of their ability to directly initiate and control RAFT polymerisation and to regulate the properties of RAFT-synthesised polymers.
The study is published in: Polymer Chemistry, Issue 1, 2017.
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