Characterization of Electrospun Poly(epsilon-caprolactone) Fibers Reinforced with Methacryllsobutyl Polyhedral Oligomeric Silsesquioxanes

摘要

Polyhedral oligomeric silsesquioxane (POSS) molecules consist of an inorganic silica core and an organic corona around the core. The chemical formula of POSS is (SiO_(1.5))_nR_n, where n = 6, 8, 10, or 12. Unique structures of POSS molecules give POSS-based materials distinct physicochemical properties such as thermal, mechanical, and surface properties. Over the past decade, owning to the biocompatibility and low-inflammatory response of POSS nano-cages, POSS-based composite materials have attracted research attention to explore their potential biomedical applications as implants.~(1,2) Polymer composites reinforced with POSS nanofillers can be prepared by chemical bonding or physical blending the POSS molecules with polymer matrices. The formation of POSS-based polymer composites therefore strongly depends on the molecular interactions between organic corona of the POSS molecules and the polymer matrix. Recent studies further demonstrate the feasibility of the use of electrospinning to fabricate POSS-based composites, especially the fluorodecyl POSS-based beaded fibers that exhibit superhydrophobicity and/or oleophobicity.~(3,4) The majority of these studies focus on the interpretation of surface properties of the electrospun substrates by analyzing advancing and receding contact angles.~(3, 4) Recent studies by our group focus on the dynamics of water droplet evaporation on POSS-based nano/microstructures. For instance, Fan et. al. shows that poly(ε-caprolactone) (PCL) and methacryllsobutyl POSS (m-iBuPOSS) blends with a fixed PCL concentration of 10 wt% can form electrospun fibers for PCL/m-iBuPOSS with blend ratios of 100/0, 90/10, 80/20, 70/30, and 50/50, respectively.~5 The topographical and chemical features of the electrospun substrates determine the energy barriers for triple line motion during droplet evaporation and therefore the water droplet evaporation dynamics as well as contact angle hysteresis.~(5,6) Thermal and molecular-level characterizations by x-ray diffractometer and differential scanning calorimeter were further performed to interpret the physicochemical properties of the electrospun PCL/m-iBuPOSS composites. Hence, this presentation will discuss some of our findings in this regard.