Solvent induced method for preparation of multi-advantage carrageenan films.

Carrageenan has good film-forming characteristics, but it is difficult to simultaneously improve its multiple performances, such as water-resistance, light transmittance and thermal stability. In this study, multi-advantage composite films were prepared by iota-carrageenan and quaternary ammonium surfactants according to solvent induced method. The weight change, FTIR and thermogravimetric analyses of the films before and after solvent inducement indicated that the inorganic counterions of iota-carrageenan were replaced by quaternary ammonium ions. By increasing surfactant content, the charge interaction with iota-carrageenan was enhanced and a new sharp peak appeared in the X-ray diffraction plots. Physical properties such as film thickness, water-resistance, water vapor transmission rate, and mechanical strength in various states were all related to the content of surfactants. In actual application, composite film with the highest waterproof property was able to maintain original state in water at 95 °C for >1.5 h. Meanwhile, composite films can be a water-induced generator with excellent self-charging and stable power output properties. A comparative study of the film transparency in terms of components and surface morphology was carried out. High light transmission, coupled with lower degradation rate in soil, suggests that these films are suitable for use as agricultural greenhouses and mulch films.