preprints.org > materials science > surfaces, coatings & films > doi: 10.20944/preprints201806.0320.v1

Preprint Article Version 1 This version is not peer-reviewed

Version 1 : Received: 19 June 2018 / Approved: 20 June 2018 / Online: 20 June 2018 (09:58:32 CEST)
Version 2 : Received: 11 July 2018 / Approved: 11 July 2018 / Online: 11 July 2018 (13:10:32 CEST)

Regenerated silk (RS) is a protein-based “biopolymer” that enables the design of new materials; here we sought to “bionic” the process of regenerated silk production by fermentation assisted method. Based on yeast’s fermentation, here we produced a living hybrid composite made of regenerated silk nanofibrils and a single-cell fungi, the Saccharomyces Cerevisiae yeast extract, by fermentation of such microorganisms at room temperature in the dissolution bath of silkworm silk fibers. The fermentation-based processing enhances the beta-sheet content of the RS, corresponding to a reduction in water permeability and CO₂ diffusion through RS/yeast thin films enabling the fabrication of mechanically robust film that enhances the food storage durability. Finally a transfer print method, which consists of transferring RS and RS/yeast film layers onto self-adherent paraffin substrate, was used for the realization of heat – responsive wrinkles by exploiting the high thermal expansion of the paraffin substrate that regulates the applied strain, resulting in a switchable coating morphology from the wrinkle-free state to a wrinkled state if the food temperature overcomes a designed threshold. We envision that such efficient and smart coatings can be applied for the realization of smart packaging that through such temperature sensing mechanism can be used to control the food storage conditions.

bionic composites; thin films; mechanical properties