One-step synthesis of sequence-controlled multiblock polymers with up to 11 segments from monomer mixture

Xiaochao Xia,Ryota Suzuki,Toshifumi Satoh,Takuya Isono,Tianle Gao

doi:10.1038/s41467-021-27830-3

Xiaochao Xia, Ryota Suzuki + Show 3 more

Open Access

https://doi.org/10.1038/s41467-021-27830-3

Copy DOI

Abstract

Switchable polymerization holds considerable potential for the synthesis of highly sequence-controlled multiblock. To date, this method has been limited to three-component systems, which enables the straightforward synthesis of multiblock polymers with less than five blocks. Herein, we report a self-switchable polymerization enabled by simple alkali metal carboxylate catalysts that directly polymerize six-component mixtures into multiblock polymers consisting of up to 11 blocks. Without an external trigger, the catalyst polymerization spontaneously connects five catalytic cycles in an orderly manner, involving four anhydride/epoxide ring-opening copolymerizations and one L-lactide ring-opening polymerization, creating a one-step synthetic pathway. Following this autotandem catalysis, reasonable combinations of different catalytic cycles allow the direct preparation of diverse, sequence-controlled, multiblock copolymers even containing various hyperbranched architectures. This method shows considerable promise in the synthesis of sequentially and architecturally complex polymers, with high monomer sequence control that provides the potential for designing materials.

Highlights

Switchable polymerization holds considerable potential for the synthesis of highly sequencecontrolled multiblock
Switchable catalysis has been applied to various metal-complex catalysts and organocatalysts, where the initial anhydride or carbon dioxide/epoxide ring-opening copolymerization (ROCOP) were followed by the ring-opening polymerization (ROP) of cyclic esters, forming various block polyesters[15,16,17,25,27,36,37,38,39]
Williams et al developed a cocatalyst system (a Cr(III) salen complex, [SalcyCrCl]; bis(triphenylphosphoranylidene)ammonium chloride, PPNCl) that exploited mechanistic switches between an anhydride/epoxide ROCOP, epoxide ROP, and a lactone ROP, resulting in the one-step synthesis of ABCBA-type pentablock terpolymers[26]. This catalytic system has shown extraordinary performance in the synthesis of well-controlled multiblock polymers, it remains limited to a three-component system

Summary

Introduction

Switchable polymerization holds considerable potential for the synthesis of highly sequencecontrolled multiblock. A well-defined pentablock polymer is successfully obtained by polymerizing a mixture of DGA/SA/NA/EGE, which displays a high level of monomer-sequence control We expected the polymerization to follow a conventional pathway (Fig. 4a), wherein the initial anhydride/epoxide ROCOP is followed by the ROP of L-LA, with propagation occurring from the termini of the resultant alternating copolymer, forming PLLA-b-P(DPMA-alt-EGE)-b-PLLA triblock copolymers[21,28].

Results

Conclusion