Studies on effect of temperature on carbonization of silk (Bombyx mori) and its application as proximity sensor

Abstract

Silk, a pyroprotein with its unique micro-structural features comprises of soft amorphous Image 1 regions containing compact Image 2-sheet crystals resulting in its potent characteristics. Annealing in inert atmosphere causes carbonization followed by graphitization of these stable Image 2-sheet-rich silk fibroins (SFs). Here we carry out systematic studies of annealed silk fibroin (Bombyx mori) in the temperature range of 200-1200°C by various analytical techniques. Herein the structural changes in SFs at different annealing temperature have been discussed using Raman, FTIR, XPS, XAES, SEM, XRD characterization techniques. Notably XPS and XAES studies were executed to examine the influence of sp2/sp3 ratio and the presence of hetero-atom on D-parameter value in silk Image 2-sheet material on gradual increase in annealing temperature. The mechanical properties of SFs were measured using UTM. The application of carbonized silk fibroins (CSF) as a proximity sensor is also investigated and proposed as a probable active material.

Keywords

• Silk fibroins
• β-Sheet
• Carbonization
• Graphitization
• XPS
• XAES