A review of semi-rigid, stilbene-containing alternating copolymers

Abstract

The synthesis and properties of sterically congested, stilbene-containing alternating copolymers are reviewed. Persistence lengths (2-6 nm) determined by size exclusion chromatography and small angle X-ray scattering techniques show that these are semi-rigid copolymers. Fully characterized polyanions and polyampholytes, prepared from organic-soluble precursors were studied, along with their respective salt and pH response behavior resulting from the semi-rigid polymer backbone. The solidstate characterization from these studies reveals a high degree of hindered rotation along the polymer backbone. The contorted structure and the hindered rotation of the polymer backbone generate inefficient chain packing, which leads to an increase of nanoporosity and higher surface areas. The semi-rigid stilbene-containing copolymers are a new class of copolymers where the increased polymer backbone rigidity leads to a wide range of polymer properties not attained with flexible polymers.

Recent advances in alternating copolymers: The synthesis, modification, and applications of precision polymers

“…is very difficult to achieve because of its steric constraints [9]. However, electron-rich trans-stilbene monomer readily radically copolymerize with electron-poor monomers like maleic anhydride or N-substituted maleimides in an alternating fashion due to both the electronic effects and reduced steric stress [140]. The first preparation of the stilbene and maleic anhydride alternating copolymer was reported in 1930 by Wagner-Jauregg [141], and it was also said to be the earliest report of a copolymerization in literature [142].…”

Enhanced Fluorescence Properties of Stilbene‐Containing Alternating Copolymers

“…It is documented that unsubstituted stilbene and maleic anhydride copolymers have poor solubility in common solvents due to strong aggregation, therefore we selected a series of tert ‐butyl carboxylate substituted stilbene and styrene alternating copolymers for this study. These copolymers are soluble in common organic solvents such as tetrahydrofuran (THF), chloroform, dimethylformamide (DMF), and N ‐methyl‐2‐pyrrolidone, which offers convenience in solution based characterizations such as size exclusion chromatography (SEC), UV–vis, and fluorescence.…”

“…It is well known that electron‐deficient maleic anhydride and maleimide monomers can readily form alternating copolymers with electron‐rich monomers such as styrene, α‐methyl styrene, stilbene, vinyl acetate, etc . Of particular interest in our group are the stilbene‐maleic anhydride/maleimide alternating copolymers . First prepared by Wagner‐Jauregg in 1930, the stilbene‐maleic anhydride copolymer was regarded to be the earliest reported synthetic copolymer in literature .…”

Zipping Polymers into Nanoparticles via Intrachain Alternating Radical Copolymerization

“…Specifi cally, stilbene derivatives, maleic anhydride, and maleimide derivatives are known to undergo strictly alternating polymerization with little to no homopolymerization occurring. [ 18 ] This effect can be quantized in the form of reactivity ratios, which arise from the rate constants of the propagation reactions of each possible radical with each monomer. Alternating copolymerizations result in cases where the reactivity ratio for each monomer is approximately equal to zero; that is, r 1 ≈ r 2 ≈ 0.…”

“…Electron rich “donor” monomers such as styrene or stilbene are known to undergo alternating radical copolymerizations with electron deficient “acceptor” monomers such as maleic anhydride (MA) or maleimide derivatives. Specifically, stilbene derivatives, maleic anhydride, and maleimide derivatives are known to undergo strictly alternating polymerization with little to no homopolymerization occurring . This effect can be quantized in the form of reactivity ratios, which arise from the rate constants of the propagation reactions of each possible radical with each monomer.…”