pH-Controlled Stereoregular Polymerization of Poly(methyl methacrylate) in Vesicle Membranes.

Here, we report a pH-controlled stereoregular polymerization of methyl methacrylate (MMA) inside the membrane of H20-COOH hyperbranched polymer vesicles using a common radical polymerization process. The vesicle size decreases from 745 to 214 nm with an increase of solution pH from 2.60 to 7.26, and the isotacticity of the obtained polymethyl methacrylates (PMMAs) is accordingly elevated from 9 to 35%. The obtained isotactic-rich PMMAs show a lower glass transition temperature depending on the isotacticity than the commercial random PMMAs. A mechanism study according to the in situ Fourier transform infrared measurements indicates that the control of polymer isotacticity results from the monomer conformation confined effect inside the thin vesicle membranes. The present study provides a new method to realize the preparation of isotactic polymers with the characteristics of facile synthesis, pH controllability, and a green polymerization process in aqueous solution as well as under mild reaction conditions of ambient temperature and pressure.

Mussel-Inspired Alternating Copolymer as a High-Performance Adhesive Material Both at Dry and Under-Seawater Conditions.

Marine mussels have the ability to cling to various surfaces at wet or underwater conditions, which inspires the research of catechol-functionalized polymers (CFPs) to develop high-performance adhesive materials. However, these polymeric adhesives generally face the problems of complex synthetic route, and it is still high challenging to prepare CFPs with excellent adhesive performance both at dry and underwater conditions. Herein, a mussel-inspired alternating copolymer, poly(dopamine-alt-2,2-bis(4-glycidyloxyphenyl)propane) (P(DA-a-BGOP)), is synthesized in one step by using commercially available monomers through epoxy-amino click chemistry. The incorporation of polar groups and rigid bisphenol A structures into the polymer backbone enhances the cohesion energy of polymer matrix. The alternating polymer structure endows the polymers with high catechol content and controlled polymer sequence. As a result, P(DA-a-BGOP) exhibits a strong bonding strength as high as 16.39 ± 2.13 MPa on stainless steel substrates after a hot pressing procedure and displays a bonding strength of 1.05 ± 0.05 MPa on glass substrates at an under-seawater condition, which surpasses most commercial adhesives.