Precise synthesis of dendron-like hyperbranched polymers and block copolymers by an iterative approach involving living anionic polymerization, coupling reaction, and transformation reaction

Abstract

Dendritic hyperbranched poly(methyl methacrylate)s (PMMA)s, whose branched architectures resemble the "dendron" part(s) of dendrimer, were synthesized by an iterative methodology consisting of two reactions in each iteration process: (a) a coupling reaction of α-functionalized, living, anionic PMMA having two tertbutyldimethylsilyloxymethylphenyl (SMP) groups with benzyl bromide (BnBr)-chain-end-functionalized PMMA, and (b) a transformation reaction of the introduced SMP groups into BnBr functionalities. These two reactions, (a) and (b), were repeated three times to afford a series of dendron-like, hyperbranched (PMMA)s up to third generation. Three dendron-like, hyperbranched (PMMA)s different in branched architecture were also synthesized by the same iterative methodology using a low molecular weight, functionalized 1,1-diphenylalkyl anion prepared from sec-BuLi and 1,1-bis(3-tert-butyldime-thylsilyloxymethylphenyl)ethylene in the reaction step (b) in each iterative process. Furthermore, structurally similar, dendron-like, hyperbranched block copolymers could be successfully synthesized by the iterative methodology using α-functionalized, living, anionic poly(2-(perfluorobutyl) ethyl methacrylate) (PRfMA) in addition to α-functionalized, living PMMA. Accordingly, the resulting block copolymers were comprised of both PMMA and PRfMA segments with different sequential orders. After the block copolymers were cast into films and annealed, their surface structures were characterized by angle-dependent XPS and contact angle measurements. All three samples showed significant segregation and enrichment of PRfMA segments at the surfaces.

Synthesis of Dendrimer‐Like Star‐Branched Poly(methyl methacrylate)s of Generations Consisting of Four Branched Polymer Chains at Each Junction by Iterative Methodology Involving Coupling and Transformation Reactions

“…Thus importantly, 3 could be synthesized from 1 used as a key functional material in the previous synthetic methodology. [17][18][19][20] The 3 thus synthesized was reacted with sec-BuLi to convert to a 1:1 adduct anion, with which the living anionic polymerization of MMA was carried out in THF at À78 8C for 1 h. Prior to the polymerization, a 5-fold excess of LiCl was added to narrow the molecular weight distribution. A polymer yield was quantitative.…”

“…[19] By utilizing the same methodology, structurally similar hyperbranched block copolymers comprising PMMA segments and either poly(2-hydroxyethyl methacrylate) or poly(2-(4-perfluorobutyl)ethyl methacrylate) segments could also be synthesized. [17,20] Since the synthetic procedure is based on an ''arm-first'' termination methodology using pre-made a-functionalized living (PMMA)s and quantitative two reactions, the resulting polymers all are well-defined in branched architecture and precisely controlled in chain length.…”

Temperature controllable hplc column for preparative fractionation of polymers

“…[29][30][31] Such prepared diblock copolymers may contain homo-polymer precursor of the first fed monomer to some extent due to the inadvertent termination when the second monomer is added. It is known to be serious when the second monomer is acrylates.…”

Synthesis and characterization of organic light-emitting copolymers containing naphthalene

“…It also causes an increase in the solubility and prevents the generation of excimers due to molecular interaction. 15,[22][23][24][25][26][27][28][29][30][31][32][33][34]36,37 Therefore, it creates a highly efficient material.…”