Tuned interactions within inclusion complex to generate electrospun matrices of superior strength

Abstract

The utilization and applications of biopolymer based electrospun matrices has expanded in various fields because of their advantageous features, however due to the poor mechanical strength their true potential has still not been realized. Enhancing mechanical strength of electrospun matrices is a long sought-after goal which is achieved by maximizing the interactions in inclusion complex (IC) of poly(ɛ-caprolactone) (PCL) with urea, in this work. The ratio of urea was varied with respect to PCL and changes in the enthalpy of fusion (ΔHf) for IC thus formed were analyzed using DSC. Binding efficiency (BE) of PCL and urea within the IC was calculated using ΔHf, which was reproducibly altered by varying urea to PCL ratio. The extent of hydrogen bonding between PCL and urea, varied in this way, was also confirmed by FTIR and XRD analysis. PCL and urea-based IC samples were electrospun to fabricate uniform fibrous matrices which upon selective removal of urea showed superior mechanical strength as compared to neat PCL matrix. The crystallinity of coalesced PCL was found to be significantly enhanced, up to 34%, in IC with urea as a result of better orientation of PCL chains. A memory effect on crystallization was ultimately seen where characteristics of coalesced PCL matrix were found to be retained even after dissolution of matrix in acetic acid and electrospinning it again.