Fabrication polymer nanofiber networks with regulated microstructures via RAFT polymerization of supramolecular gels in different solvents

In this article, a new diurea type gelator synthesized from heptanediamine and 2-isocyanatoethyl methacrylate was found to gel dioxane effectively. During forming the gel, the gelator molecules assembled into nano-sized fibrillary network driving by hydrogen bonds of urea groups. In cyclohexane, toluene and their mixed solvents, polymer nanofiber networks were successfully fabricated via Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization of the xerogels as both templates and monomer source. The solvent polarity was found to affect both the polymerization rate and the microstructures of polymer fibers. As more toluene was used in the mixed solvents, larger-sized fibers with improved surface roughness were obtained, together with the increased product yields. The formation mechanism of the microstructures was discussed based on MALDI-TOF-MS and TEM analytical results. Furthermore, the adsorption to acid indigo blue of the resulting samples was investigated, which indicated that the maximum adsorption capacities were correlated well with the specific surface areas of the samples.