Electrospinnability of hydrogen bonded supramolecular comb polymers based on Poly(4-vinylpyridine) and 3-pentadecylphenol

Abstract

We report on the electrospinnability of supramolecular comb polymers formed by the complexation of poly(4-vinylpyridine) (P4VP) with an amphiphilic surfactant, 3-pentadecylphenol (PDP) through hydrogen bonding. It was observed that the choice of solvent has profound influence on the rheological properties of such supramolecular comb polymers and, hence, govern the electrospinnability. The solution viscosity was found to increase in a solvent system which did not significantly interfered in the hydrogen bond formation between the P4VP and PDP. The increase in the solution viscosity of the P4VP/PDP supramolecular comb polymer plausibly was due to the formation of physical cross-links between P4VP chains driven by non-polar interactions between the surfactant tails. However, in a solvent system which screened the hydrogen bonding between the polymer and amphiphile, such increase in solution viscosity was not observed. Furthermore, the increase in the solution viscosity was not as pronounced as in the case of ionically bonded supramolecular comb polymers previously reported by us (ACS Omega 2018; 3: 15666–78). This plausibly was due to the temporal nature of the hydrogen bonds in solution because of which the relaxation time of the physical network formed was much shorter than that formed by ionically bonded supramolecular systems. Furthermore, the increase in the solution viscosity resulted in an improved electrospinnability of the supramolecular comb polymers compared to neat P4VP. These supramolecular comb polymers further demonstrated their typical mesomorphic structure in the electrospun nanofibers and were characterized by SAXS and DSC. Moreover, the PDP could be selectively removed from the electrospun nanofibers resulting in the formation of porous nanofibers. The present study provides further insight into the role of supramolecular interactions in electrospinnability and also provides an interesting approach for fabricating porous nanofibers.