화학공학소재연구정보센터
Macromolecules, Vol.41, No.12, 4275-4283, 2008
Associative polymer facilitated electrospinning of nanofibers
Electrospun nanofibers present an exciting avenue for development of novel materials with well-defined functionalities; however, broadening the scope of electrospinning to a diverse range of polymers remains a major challenge. In particular, a recurring issue in this field is the inability to spin polymers at lower concentrations in order to achieve smaller fiber diameters. This work explores the use of associative polymers as a means to overcome this limiting factor that prevents the electrospinnning of nanofibers from low-concentration polymer solutions. Hydrophobically modified alkali-soluble emulsion (HASE) polymers are comblike associative polymers with pendant hydrophobes that form a network in aqueous media consisting of both intra- and intermolecular hydrophobic junctions. Rheological measurements reveal that addition of HASE polymers in small amounts to poly(ethylene oxide) solutions leads to considerable increase in viscosity as well as dynamic moduli of the system. More importantly, these theological changes are translated into significant changes in fiber morphology, from beaded to uniform nanofibers, as well as reduction in fiber diameter. The concept of using rheology modifiers is further. extended to another associative polymer, guar galactomannan, which associates through a different mechanism. Similar improvements in fiber formation are observed, thereby lending credence to the universality of this approach.