Thermoresponsive electrospun membrane with enhanced wettability

Abstract

This study investigated the switchable wettability behavior of poly-N-(isopropyl acrylamide) (PNIPAM) and poly-(vinylidene fluoride) (PVDF) blend membranes that were fabricated using electrospinning. The wettability of the membranes was determined by water contact angle measurements. The wettability of the membranes was controlled by varying the concentration of PNIPAM in the blend. The results demonstrated that the addition of PVDF to the PNIPAM did not change the thermoresponsive behavior of PNIPAM. All PNIPAM/PVDF blend samples switched from hydrophilic to hydrophobic state when the temperature was increased from room temperature to 40 C. However, blend samples with 25 wt% PNIPAM were demonstrated to be more hydrophilic and hydrophobic compared to other samples at room temperature and elevated temperature respectively. This was attributed to the phase separation of the polymers that resulted in domains with drastically different surface energies on the surface of the fibers.

Poly(Caprolactone)‐Poly(N‐Isopropyl Acrylamide)‐Fe3O4 Magnetic Nanofibrous Structure with Stimuli Responsive Drug Release

“…PNIPAAm swelling and deswelling kinetics relies on the sample surface area and chemical composition. [ 46 ] Below the LCST, due to the strong hydrophilic property of the amide group, strong water absorption in the PNIPAAm chain segment is achieved. [ 47 ] Above the LCST the PNIPAAm chain compacts and become dehydrated.…”

“…[ 47 ] Above the LCST the PNIPAAm chain compacts and become dehydrated. [ 5,46 ] Hence, due to the presence of hydrophilic group (amide groups) of PNIPAAm an increase in swelling has been observed at 37 and 40 °C. According to Figure A, a large network expansion, due to the presence of hydrophilic groups (for example CONH), has led to a high water absorption.…”

Electrospun Janus Membrane for Efficient and Switchable Oil–Water Separation

“…This shows that the blend membrane is hydrophobic at elevated temperature. This behavior of the electrospun blend membrane is attributed to the presence of PNIPAM on the surface of the fibers . However, the enhanced wettability is attributed to the phase separation of the PNIPAM and PVDF during the electrospinning process.…”

“…This behavior of the electrospun blend membrane is attributed to the presence of PNIPAM on the surface of the fibers. [30] However, the enhanced wettability is attributed to the phase separation of the PNIPAM and PVDF during the electrospinning process. Additionally, we demonstrate that these fibrous blends are stable in water.…”

“…It is known that PNIPAM is a water soluble thermoresponsive polymer and it should either be blended with other polymers or cross‐linked to make it stable in water . In our earlier work, we blended PNIPAM with PVDF and determined the concentration of PNIPAM required in the blend to ensure that the blend is stable in water and demonstrates enhanced wettability. Our results demonstrated that when 25 wt% of PNIPAM concentration is used in the PNIPAM/PVDF blend, the membrane shows thermoresponsive behavior with enhanced wettability.…”