Wettability regulation of membranes based on biodegradable aliphatic polyester

Biodegradable aliphatic polyesters are intensively applied in food packaging, regenerative medicine, tissue engineering, water purification and flexible electronics. However, the performance of these polymers is largely hindered by their inherent hydrophobicity. Here we report a facile method for producing hydrophilic fibers based on biodegradable aliphatic polyesters. Specifically, poly (lactide caprolactone) (PLCL) was dissolved in solvent systems containing trifluoroacetic acid (TFA) for electrospinning. Increasing TFA proportion or dissolving time successfully decreased the water contact angle (WCA) of PLCL fibrous membranes from 124° to 67°. The mechanism of wettability alteration was elucidated and ascribed to the generation of hydrophilic carboxyl acid and hydroxyl groups vis the acid hydrolysis reaction that cleaved PLCL chains. The exponential relationship between molecular weight and WCA confirmed the mechanism, pointing out an in-situ way for accurately controlling the wettability of PLCL. The efficacy of using hydrophilic PLCL membranes in biomedical engineering and environmental protection was preliminarily verified. Janus membranes with unidirectional water transfer were also fabricated. The versatility of our method was further proven by the switchable wettability of fibers spun from various biodegradable polyesters, including polylactide, polycaprolactone and poly (lactic-glycolic acid). We anticipate this work will broaden the application fields of biodegradable aliphatic polyesters. [Display omitted] •Hydrophobic membranes based on biodegradable aliphatic polyester are switched to hydrophilic via acid hydrolysis.•The mechanism of wettability transformation is elucidated through studying the molecular structure of the polymer.•Membranes with switchable wettability are preferred in biomedical engineering, oil/water separation and liquid transfer.•Versatility of our method is proved in a variety of biodegradable aliphatic polyesters.