PVA–Polystyrene-Based Polymer Films with Water-Induced Shape-Memory Effect

In this work, a series of novel water-induced shape-memory composite films are prepared on the basis of poly(vinyl alcohol)-polystyrene (PVA–PSX) through one pot in situ polymerization method. The neat PVA film is modified to PVA–PSX film by loading calibrated amount of styrene, and the resulted film exhibits high mechanical strength (tensile strength ∼40 MPa, tensile strain ∼315%, Young's modulus ∼0.25 MPa and toughness ∼5 MJ/m3). More importantly, water-induced shape-memory behavior is observed for the PVA–PSX composite films and among various proportions, PVA–PS3 film (3 v/v% of styrene content) shows the fastest shape recovery rate (160 s). The relative low value of storage modulus and glass transition temperature of the PVA–PS3 films is attributed to water-induced shape recovery. The desirable and multifaceted properties of the PVA–PSX composite film, such as optimum transparency, improved water resistance, enhanced shape recovery, diminished UV-light transmission, and effectual antimicrobial activity, propound that the composite film is a suitable candidate for preparing packaging materials in food and cosmetic industries.