Biobased Polymers\nEnabling the Synthesis of Ultralong\nSilver Nanowires and Other Nanostructures

Conventional polyol synthesis of silver nanowires has\nexclusively\nrelied on polyvinylpyrrolidone (PVP), a nonbiodegradable polymer with\nno viable alternatives. The underlying reaction mechanism remains\nunclear. Herein, we discovered a new sustainable solution by employing\nbiobased cellulose derivatives, including hydroxyethyl cellulose (HEC),\nas effective substitutes for PVP. Under mild reaction conditions (125\n°C, ambient pressure), HEC facilitates the growth of ultralong\nsilver nanowires (>100 μm) from penta-twinned silver seeds\nthrough\na four-stage kinetic process. Theoretical calculations further reveal\nthat HEC is physiosorbed onto the silver surfaces, while the presence\nof bromide ions (Br<sup>–</sup>) facilitates the evolution\nof seeds into nanowires. By varying halide ion concentrations and\nsubstitution in different cellulose derivatives, we successfully synthesized\nsilver nanostructures with additional intriguing morphologies, including\nquasi-spherical nanoparticles, bipyramids, and nanocubes. Furthermore,\ntransparent conductive films fabricated from ultralong silver nanowires\nsynthesized with HEC demonstrated superior performance compared to\nthose made with PVP-synthesized nanowires.