Two-dimensional materials modified layered double hydroxides: A series of fillers for improving gas barrier and permselectivity of poly(vinyl alcohol).

A series of modified 2D nanosheets (graphene oxide-layered double hydroxide, GO-LDH; boron nitride-LDH, BN-LDH; and molybdenum disulfide-LDH, MoS 2 -LDH) are prepared via a cost-effective, environmentally-friendly, and effortless method based on the concept of electrostatic interaction. The modified 2D nanosheet/Poly(vinyl alcohol) (PVA) nanocomposite films show a comprehensive improvement of physicochemical properties. Among the synthesized films, the O 2 barrier performance of the 1% GO-LDH/PVA nanocomposite film (1.44 × 10−13 cm3 cm/cm2·s·cmHg) is 25-fold higher than that of the pure PVA film (3.68 × 10−12 cm3 cm/cm2·s·cmHg). The 1% GO-LDH/PVA shows tremendous improvement in tensile strength (84.7 MPa) and modulus (3032 MPa) values than the PVA film (46.7 and 371 MPa). Furthermore, the 2% BN-LDH/PVA nanocomposite shows the H 2 /CO 2 permselectivity value of 102.5, which is superior to the Robeson upper bound and most reported separation films. In addition to the improved gas barrier and permselectivity performances, an exceptional combination of the thermal stability, tensile strength/modulus, flexibility, and transparency of the nanocomposite film could lead to applications in food packaging, H 2 purification, and CO 2 capture. Image 1 • A series of modified 2D nanosheets (GO-LDH, BN-LDH, and MoS 2 -LDH) were successfully prepared. • Modified 2D nanosheets/PVA films were prepared by a simple solution casting method. • The O 2 barrier performance of nanocomposite film is 25-fold higher than that of the pure PVA. • H 2 /CO 2 permselectivity (102.5) of 2% BN-LDH/PVA film transcends the Robeson upper bound. [ABSTRACT FROM AUTHOR]