Evolution of Microphase Separation with Variations of Segments of Sequence-Controlled Multiblock Copolymers

Abstract

Multiblock copolymers (MBCPs) are an emerging class of materials that are becoming more accessible in recent years. However, to date there is still a lack of fundamental understanding of their physical properties. In particular, the glass transition temperature (Tg) which is known to be affected by the phase separation has not been well characterized experimentally. To this end, we report the first experimental study on the evolution of the Tgs and the corresponding phase separation of linear MBCPs with increasing number of blocks while keeping the overall degree of polymerization (DP) constant (DP = 200). Ethylene glycol methyl ether acrylate (EGMEA) and tert-butyl acrylate (tBA) were chosen as monomers for reversible addition–fragmentation chain transfer polymerization to synthesize MBCPs. We found the Tgs (as measured by differential scanning calorimetry) of EGMEA and tBA segments within the MCBPs to converge with increasing number of blocks and decreasing block length, correlating with the loss of the...