Solid‐Phase Radical Polymerization of Halogen‐Bond‐Based Crystals and Applications to Pre‐Shaped Polymer Materials

Abstract

Liquid vinyl monomers were converted into solid crystals via halogen bonding. They underwent solid‐phase radical polymerizations through heating at 40 °C or ultraviolet photo‐irradiation (365 nm). The X‐ray crystallography analysis showed the high degree of monomer alignment in the crystals. The polymerizations of the solid monomer crystals yielded polymers with high molecular weights and relatively low dispersities because of the high degree of the monomer alignment in the crystal. As a unique application of this system, the crystalized monomers were assembled to pre‐determined structures, followed by solid‐phase polymerization, to obtain a two‐layer polymer sheet and a three‐dimensional house‐shaped polymer material. The two‐layer sheet contained a unique asymmetric pore structure and exhibited a solvent‐responsive shape memory property and may find applications to asymmetric membranes and polymer actuators.

2D conjugated microporous polyacetylenes synthesized via halogen-bond-assisted radical solid-phase polymerization for high-performance metal-ion absorbents

“…The grain sizes of cocrystals 1•6, 1•7, and 1•8 were ~500-1000 nm, according to the transmission electron microscopy (TEM) analysis (Supplementary Figs. [23][24][25]. The grains would be single cocrystals or assemblies of cocrystals, which were embedded in the DMPA (photo-initiator) matrix.…”

“…The grain sizes were virtually the same before and after the SPP (Supplementary Figs. [23][24][25], suggesting that the origin of the grains of the formed polymers (below) is the grains of the monomer cocrystals.…”

“…In our previous work, we developed a halogen-bond (XB)-assisted free-radical solid-phase polymerization (SPP). Several vinyl monomers were converted to solid cocrystals via XB, and the resultant alignment of the monomers facilitated radical propagation to yield high-molecular-weight vinyl polymers 24,25 .…”