Influence of self-complementary hydrogen bonding on solution rheology/electrospinning relationships

A series of poly(alkyl methacrylate)s that contained either pendant carboxylic acid or self-complementary multiple hydrogen bonding (SCMHB) groups were synthesized to determine the influence of intermolecular associations on solution rheology and electrospinning performance. The cosolvent composition was varied in order to control the dielectric constant of the electrospinning solvent. By controlling the dielectric constant of the solvent, intermolecular interactions were systematically screened, and the influence of hydrogen bonding on electrospun fiber morphology was determined. While the diameter of the electrospun poly(methyl methacrylate) (PMMA) fibers were in excellent agreement with previously developed predictions, the diameter of the electrospun poly(methyl methacrylate-co-methacrylic acid) (PMMA-co-PMAA) fibers were smaller than predicted when electrospun from dimethyl formamide (DMF). The smaller PMMA-co-PMAA fibers were attributed to dissociation of the carboxylic acid group, which resulted in increased solution conductivity. The poly(methyl methacrylate-co-SCMHB methacrylate) (PMMA-co-SCMHB) displayed significant hydrogen bonding associations with decreasing solvent dielectric constant (D) which resulted in increased viscosity and lower entanglement concentration (Ce). Moreover, strong hydrogen bonding between the SCMHB groups in relatively nonpolar solvents increased the apparent molecular weight of the copolymers, and significantly larger electrospun fibers than predicted were obtained.