Precise Synthesis of Exact Graft Polystyrenes with Branches from Two to Five in Number by Iterative Methodology Based on Living Anionic Polymerization

Abstract

The precise synthesis of a series of exact graft polystyrenes (PS)s with two, three, four, and five branches by a new iterative methodology based on living anionic polymerization is described. The methodology involves only three reaction steps in each iterative reaction sequence, i.e., (1) a transformation reaction of the 3-(tert-butyldimethylsilyloxy)propyl (SiOP) group into 3-bromopropyl function via deprotection of the silyl group, (2) a linking reaction of α-SiOP-ω-1,1-diphenylethylene (DPE)-functionalized polymer anion with α-terminal 3-bromopropyl-functionalized PS to prepare the backbone chain with the incorporation of a DPE moiety in the chain, and (3) an addition reaction of PSLi with the DPE moiety in the backbone to introduce a PS branch. By repeating the reaction sequence five times, we have succeeded in successively synthesizing a series of exact graft (PS)s having up to five branches for the first time. In the graft (PS)s all thus synthesized, not only the molecular weights of both backbone and branch chains but also the number and position of branch chains were precisely controlled.

Precise Synthesis of Macromolecular Architectures by Novel Iterative Methodology Combining Living Anionic Polymerization with Specially Designed Linking Chemistry

“…Although the physical and mechanical properties as well as morphology of (GP) are significantly influenced by such three structural parameters, their relationships have not been enough elucidated due to the synthetic difficulty of (EDGP) [ 1 , 2 , 89 , 90 , 91 ]. In practice, various (GP)s have been synthesized so far, but all of them are not (EDGP)s, except for the PIs– graft –PSt reported by Hadjichristidis et al [ 88 ] and several graft polymers synthesized by Hirao et al, which will be introduced in this section [ 92 , 93 , 94 , 95 , 96 , 97 ].…”

“…If the stoichiometry is deviated in the reaction, many side products difficult in separation are by-produced. Later, an (EDGP) having five graft chains was successfully synthesized by an improved methodology based on the termination procedure [ 92 ].…”

Combining Living Anionic Polymerization with Branching Reactions in an Iterative Fashion to Design Branched Polymers

“…[123] In contrast to the methodology introduced above, a termination reaction is used for chain growth in this methodology, as illustrated in Scheme 15. The following three reaction steps are employed in each iterative synthetic sequence: (a) a transformation reaction of the a-terminal 3-tert-butyldimethylsilyloxypropyl (SiOP) group into a 3-bromopropyl function via deprotection of the SiOP group, (b) a coupling reaction of the resulting Combining Living Anionic Polymerization with Branching Reactions in .…”

Synthesis of Bottlebrush Polystyrenes with Uniform, Alternating, and Gradient Distributions of Brushes Via Living Anionic Polymerization and Hydrosilylation

“…The control of branch point spacing has also been carried out in virtue of living anionic (co)polymerization of 1,1‐diphenylethlene (DPE) end‐capped macromonomers . However, as the DPE cannot be homopoly­merized, the spacing between brushes could be well‐regulated when using anionic polymerization.…”

“…The bottlebrush polymers have been defi ned as multiple polymeric brushes which are densely grafted onto The control of branch point spacing has also been carried out in virtue of living anionic (co)polymerization of 1,1-diphenylethlene (DPE) end-capped macromonomers. [19][20][21] However, as the DPE cannot be homopolymerized, the spacing between brushes could be wellregulated when using anionic polymerization. Multiple reaction steps could introduce additional impurities and generate defects in the spacing control of branch points.…”