Poly(vinyl alcohol)/layered double hydroxide (PVA/LDH) composite films with different LDH contents have been fabricated through casting with an in situ hydrothermal treatment.Wide angle X-ray diffraction (WAXD) results show the characteristic (003) diffraction reflection peak of LDH layers and the corresponding peak becomes stronger with the increase of LDH content

and the size of LDH layers can be tuned by the concentration of reactant.Lower reactant concentration leads to small size of LDH particles while higher concentration gives LDH particles with large size.LDH particles are homogeneously dispersed in PVA matrix as evidenced by SEM observations.The tensile strength and the elastic modulus of PVA films are improved by introducing LDH particles.With the LDH content of 1.0 wt%

the tensile strength and elastic modulus of the corresponding composite films are improved by about 105.4% and 133.2%

respectively

compared with those of a neat PVA film.It is believed that most OH groups of PVA undergo interfacial H-bonding with the LDH layers and other PVA chains

which might be account for the improvement of mechanical properties.Interesting thing is that the in situ PVA/LDH composite aqueous solution shows lower viscosity than that of PVA aqueous solution and the viscosity decreases with LDH content

which is in strong contrast to that by traditional simple mixing.LDH layers are considered to shield the entanglement of PVA chains and thus lead to decreasing solution viscosity.Furthermore

the anti-absorbent of water for the composite films are also improved without losing transparency

while the improvement of gas barrier cannot be observed until the loading of LDH reaches to 3.0 wt%.