High performance of alginate/polyvinyl alcohol composite film based on natural original melanin nanoparticles used as food thermal insulating and UV–vis block

Light is a major factor in promoting food aging and deterioration, especially for ultraviolet (UV) light. Herein, bioinspired dopamine–melanin solid nanoparticles with strong absorption at a wide range of 200–2500 nm were first incorporated into alginate/polyvinyl alcohol to fabricate film materials in this work for UV–vis block, and this also brings excellent thermal insulating properties to the materials. In addition, in order to obtain a material with excellent performance, particles of uniform size of about 100 nm are obtained by fractional centrifugation. It was found the mechanical, UV–vis block and thermal insulating properties were improved significantly compared with the control samples. This study provides a strategy to design a non-polluting, biodegradable, biocompatible film with excellent mechanical properties that can be used in UV–vis barriers and has potential applications in thermal insulating materials for food preservation.