Disulfide‐Bridged Dynamic Covalent Triazine Polymer Thin Films by Interface Polymerization: High Refractive Index with Excellent Optical Transparency

Abstract

Exploring innovative strategies for molecular structuring of dynamic materials that combine self-correcting intrinsic reversibility with the robustness of covalent bonds, has been a long-standing objective from applications perspective in fields ranging from molecular engineering to nanotechnology and interfacial science. To establish dynamic covalent chemistry approaches combined with interfacial polymerization, herein, a distinct synthetic approach is reported to develop disulfide-bridged 2D polymeric C$_3$N$_3$S$_3$ triazine thin-films by interfacial thiol-disulfide dynamic exchange process crosslinking tritopic planar 1,3,5-triazine-2,4,6-trithiol molecular tectons via intermolecular disulfide formation in the presence of I$_2$ vapors at the air/water interface under redox condition. The resulting centimeter-scale polymeric thin-films are covalently cross-linked, dynamic in nature, featuring tunable thickness (6–200 nm) and significant morphological variations are realized under the influence of varying reaction time, concentration and types of reducing agents. Notably, C$_3$N$_3$S$_3$ polymer thin films exhibit a transflectance of around 99.5% in the range from 430 to 1800 nm, show high refractive indices (1.730–1.488) and optical anisotropy with uniaxial negative birefringence. The C$_3$N$_3$S$_3$ free-standing polymer thin-films can be easily transferred to different substrates or possibly into application-relevant forms for device fabrications, making this useful from materials application perspective