Enhanced Stretchability of Azide-Functionalized Semiconducting CNT Thin Films via UV-Crosslinking

Single-walled carbon nanotubes (SWCNTs) represent promising candidates for stretchable electronics;
however, simultaneously realizing semiconducting purity and mechanical durability in CNT-based networks
remains a significant challenge. Here, we report an azide-functionalized conjugated polymer designed to
selectively encapsulate semiconducting SWCNTs (s-SWCNTs), facilitating their isolation from metallic
SWCNTs and enabling the fabrication of high-purity semiconducting networks. When deposited on
elastomeric substrates, UV irradiation triggers the activation of azide moieties to produce reactive nitrene
intermediates, which promote covalent bond formation at both CNT–CNT junctions and the CNT–substrate
interface. This yields a mechanically stable, interconnected network with strong interfacial adhesion to the
underlying substrate. Consequently, the UV-crosslinked films demonstrate substantially improved
stretchability relative to their non-crosslinked counterparts, as evidenced by film-on-elastomer
characterization. The enhanced mechanical behavior is ascribed to efficient stress transfer through the
covalently bonded CNT network. Collectively, these findings highlight that azide-functionalized polymer
wrapping coupled with UV-induced crosslinking offers a versatile and effective strategy for concurrently
achieving selective semiconducting CNT networks and mechanically robust stretchable electronic materials.