Chiral polylactic acid-based composite membrane with hydrophilic modification for efficient degradation of organic pollutants by harvesting mechanical energy

Efficient and recyclable piezoelectric polymers are promising materials for environmental purification and energy regeneration. In addition to the most widely studied polyvinylidene fluoride (PVDF), chiral poly-L-actic acid is an attractive biodegradable alternative that also exhibits piezoelectricity when highly oriented and polarized through electrospinning. In this work, highly-oriented electrospun fibers of poly-L-lactic acid (PLLA) doped with the dopamine-modified barium titanate (HBTO) are fabricated and subsequent hydrophilic modification yields a piezocatalytic membrane (HBTO@HPLLA) rich in catalytic active sites. The interfacial interaction between HBTO and PLLA is enhanced via hydrogen bonding, significantly improving the piezoelectric activities of the resulting composite membrane. Consequently, HBTO@HPLLA degrades Bisphenol A (BPA) in water under ultrasonic vibration at a rate constant 4.3 times higher than pure PLLA. Furthermore, when adhered to the blades of a propeller with mechanical stirring at 1200 rpm, the HBTO@HPLLA membrane also demonstrates high efficiency in BPA removal. This approach offers a promising strategy for developing biocompatible piezoelectric materials utilizing natural low-frequency mechanical energy for environmental remediation.