Cationic Polymerization: From Photoinitiation to Photocontrol

Abstract

During the last 40 years, researchers investigating photoinitiated cationic polymerizations have delivered tremendous success in both industrial and academic settings. A myriad of photoinitiating systems have been developed, thus allowing polymerization of a broad array of monomers (e.g., epoxides, vinyl ethers, alkenes, cyclic ethers, and lactones) under practical, inexpensive, and environmentally benign conditions. More recently, owing to progress in photoredox catalysis, photocontrolled cationic polymerization has emerged as a means to precisely regulate polymer chain growth. This Minireview provides a concise historical perspective on cationic polymerization induced by light and discusses the latest advances in both photoinitiated and photocontrolled processes. The latter are exciting new directions for the field that will likely impact industries ranging from micropatterning to the synthesis of complex biomaterials and sequence-controlled polymers.

Mono-substitution of symmetric diesters: selectivity of Mycobacterium smegmatis acyltransferase variants

“…While vinyl esters are prone to follow radical polymerization, functional groups like vinyl ethers are typically used in cationic polymerization. 24 The steric properties for BVE are similar to those of 1-octanol and thus similar reactivities for the two acyl acceptors were anticipated. The results shown in the lower row in Fig.…”

Precise growth of polymer brushes on silica-based nanocomposites via visible-light-regulated controlled radical polymerization

“…[12][13][14] In the pursuit of solar-driven synthesis of natural polymers with well-preserved chain terminus fidelity as well as composition, spatiotemporal and sequence control, extensive research has been devoted to the development and exploitation of visible-light-mediated modern polymer synthesis for precise control over the polymerization procedures. [15][16][17][18][19][20][21][22][23][24] Arising from its highly advantageous characteristics including low cost, user-friendly operation, fast initiation efficiency and convenient spatiotemporal polymerization modulation, photoinduced electron/energy transfer reversible addition fragmentation chain transfer (PET-RAFT) polymerization enables a versatile toolkit for controlled polymerizations of diverse functional monomers from nanomaterials and is universal in its specificity to satisfy the energetic criteria for conducting such polymerization, which would be otherwise inaccessible by thermal counterparts. [25][26][27][28][29] To the best of our knowledge, the current work is the first example to illustrate a systematic method to propagate well-defined polymer brushes directly from the surface of various silica-assisted nanomaterials using a PET-RAFT approach.…”

Photosensitive Formulation for Additive Manufacturing-3D Printing

“…In that later case there is no need of Photoinitiator. Photoinitiators for cationic polymerization (epoxy and vinyl ether resins), upon exposure to UV light produce strong acid [4,5] according the following scheme :…”