Comparative analysis of electrospun PNIPAAm blends with some biodegradable polymers

ABSTRACT

In this work, electrospun fibers of poly(butylene adipate-co-terephthalate)/poly(N-isopropylacrylamide), PBAT /PNIPAAm, and ecovio^®/PNIPAAm blends were obtained. These blends presented a thermoresponsive behavior including a sudden response to temperature variation between 32 and 35 ºC. The addition of PNIPAAm to PBAT and ecovio^® solutions significantly improved the electrospinability of both solutions as blends, allowing them to form rounded fibers without defects and with diameters varying between 1000 and 1700 nm. The analysis of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) spectra for PBAT/PNIPAAm and ecovio^®/PNIPAAm electrospun fibers revealed that the electrospinning process does not lead to the formation of strong intermolecular interactions, such as hydrogen bonds, between the constituents of the studied blends’ electrospun fibers. Significant drop water contact angle variation as a function of temperature was observed for both PBAT/PNIPAAm and ecovio^®/PNIPAAm electrospun fibers; both presented PNIPAAm’s hydrophilic-hydrophobic transition in the range between 32 and 35 ºC. Comparing PBAT/PNIPAAm and ecovio^®/PNIPAAm electrospun fibers, the former was revealed to be more temperature-sensitive than the latter, regarding changes in wettability as the former presented larger gaps in drop water contact angle values compared to the latter. With these results, these blends in the form of electrospun fibers may have a potential application in the field of cell adhesion/detachment.

Keywords
PBAT; ecovio^®; PNIPAAm; blends; fibers