Main- and side-chain sequence-regulated vinyl copolymers were prepared by a combination of iterative atom transfer radical additions (ATRAs) of vinyl monomers for side-chain control and 1:1 or 2:1 alternating radical copolymerization of the obtained side-chain sequenced "oligomonomers" and vinyl comonomers for main-chain control. A complete set of sequence-regulated trimeric vinyl oligomers of styrene (S) and/or methyl acrylate (A) were first synthesized via iterative ATRAs of these monomers to a halide of monomeric S or A unit (X-S or X-A) under optimized conditions with appropriate ruthenium or copper catalysts, which were selected depending on the monomers and halides. The obtained halogen-capped oligomers were then converted into a series of maleimide (M)-ended oligomonomers with different monomer compositions and sequences (M-SSS, M-ASS, M-SAS, M-AAS, M-SSA, M-ASA, M-SAA, M-AAA) by a substitution reaction of the halide with furan-protected maleimide anion followed by deprotection of the furan units. These maleimide-ended oligomonomers were then radically copolymerized with styrene or limonene to enable the 1:1 or 2:1 monomer-sequence regulation in the main chain and finally result in the main- and side-chain sequence-regulated vinyl copolymers with high molecular weights in high yield. The properties of the sequence-regulated vinyl copolymers depended on not only the monomer compositions but also the monomer sequences. The solubility was highly affected by the outer monomer units in the side chains whereas the glass transition temperatures were primarily affected by the two successive monomer sequences.

We propose a novel strategy of monomer sequence regulation in main and side chains of vinyl copolymers using sequential atom transfer radical addition (ATRA) for maleimide-ended sequence-regulated vinyl "oligomonomers" and their alternating radical copolymerization with styrene. To establish this strategy, a series of sequence-regulated vinyl oligomers were prepared by the ATRA of styrene (S) or methyl acrylate (A) to a halide-possessing A or S unit (methyl α-bromopropionate or 1-phenylethylhalide). The obtained halide-ended sequence-regulated vinyl oligomers were converted into maleimide-ended oligomonomers by S N 2 reaction with the potassium salt of furan-protected maleimide (M) followed by deprotection. The maleimide-ended oligomonomers were then radically copolymerized with styrene in an alternating fashion to result in sequence-regulated vinyl copolymers consisting of a controlled monomer sequence (SA, AS, AA, and SS) in the side chain and an alternating sequence (MS) in the main chain. The solubility of the copolymers depended on not only the monomer composition but also the sequence of the side chains, whereas the thermal properties were negligibly affected by the side-chain monomer sequences.

We have developed a method to obtain a polymer gel consisting of a relatively homogeneous network structure composed of polymers with a narrow molecular weight simply by mixing the necessary compounds. In this method, a radical chain polymerization reaction with a fast reaction rate is combined with a radical addition cross-linking reaction that has a sufficiently slow reaction rate compared with the polymerization reaction. For the polymerization reaction, a multifunctional initiator with a strictly controlled number of polymerization initiation sites was used to prepare a star polymer with a chain number and length determined by living radical polymerization. In the cross-linking reaction, a multifunctional terminating agent was used to prepare a star polymer from a polymer with a narrow molecular weight via living radical polymerization followed by coupling with multiple polymer chains using a termination reaction. As a result, two kinds of reactions with greatly different kinetics occurred sequentially only when all of the compounds were mixed and allowed to stand at a constant temperature, and a relatively homogeneous network structure comprising cross-linked polymers with a low molecular weight distribution was inherently constructed.

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Sequence-regulated vinyl copolymers with acid and base monomer units were prepared via atom transfer radical addition and alternating radical copolymerization.