Precision Synthesis of Conjugated Multiblock Copolymers via Living Polymerization: Molecular Architecture Control for Enhanced Stretchability and Charge Transport

The development of stretchable electronic devices requires addressing the fundamental trade-off between mechanical deformability and charge carrier mobility. While conjugated polymers possess excellent charge transport capabilities, their rigid backbones limit large mechanical deformation. Conjugated multiblock copolymers (CMPs), combining semiconducting and elastomeric segments within a single polymer architecture, have been explored to overcome this limitation. However, most reported CMPs are based on conjugated blocks prepared by step-growth polymerization, where precise control over molecular weight, dispersity (Đ), and end-group fidelity remains challenging. As a result, poorly defined mixtures of multiblock copolymers and homopolymers can form, hindering reliable structure–property relationships.

In this study, we utilize Suzuki–Miyaura catalyst-transfer polymerization (SCTP) to prepare poly(3-hexylthiophene)-diol precursors with controlled molecular weight, narrow dispersity, and defined end-group structures. By comparing P3HT-living, P3HT-mix, and P3HT-step precursors and coupling them with polydimethylsiloxane (PDMS), we construct CMPs with controlled block compositions (0–75 mol%) and block lengths. This enables quantitative evaluation of how precursor precision influences crystallinity, phase separation, hole mobility, and stretchability. Notably, CMPs derived from high-molecular-weight P3HT-living precursors exhibit stretchability above 300% while retaining high hole mobility of 10⁻³–10⁻² cm² V⁻¹ s⁻¹. In contrast, CMPs from less-defined precursors show lower molecular weights and reduced stability. These findings demonstrate that precision living polymerization provides a powerful platform for elucidating structure–property relationships and designing high-performance stretchable semiconducting polymers.