Facile strategy of Fe3+ rich collagen-based composite hydrogel for antibacterial, electricity harvesting and sensing applications

Conventional hydrogels have poor conductivity and low stretchability, limiting their practical applications for different purposes. Herein, collagen (CL) based, poly(vinyl alcohol) (PVA) and glutaraldehyde (GT) cross-linked ferric ion (Fe 3+ ) rich highly conductive CL/GT/PVA/Fe hydrogel was developed. The presence of high CL, PVA and Fe 3+ ions, together with the effective Fe 3+ complexes formation, delivers the hydrogel with some particular assigns, such as high ionic conductivity (3.44 S.m −1 ) and antibacterial activity ; furthermore, a very high stretchability. The CL/GT/PVA/Fe hydrogel demonstrated excellent mechanical properties, where the highest tensile strength of the hydrogels was ∼204.5 kPa at an elongation of 674 %, and the highest compressive strength was ∼0.39 MPa, with the highest stretchability of 81.67 %. The strengths are enhanced significantly by the incorporation of Fe 3+ ions because of the formation of effective complexation of Fe 3+ with rich hydroxyl and carboxyl groups of PVA and CL. As a flexible strain sensor, the CL/GT/PVA/Fe hydrogel with excellent conductivity manifests high sensitivity in human motion monitor. The hydrogels’ sufficient –OH and –COOH groups play a key role in imparting moist-induce electricity supply and the highest 173 mV of open circuit voltage (V oc ) generated during moisture spray. • The main raw material CL was extracted from raw trimmings. • The CL/PVA/GT/Fe hydrogel possesses antibacterial, moist-generator and conductive properties. • The CL/PVA/GT/Fe hydrogel can detect the physiological activity signals precisely for the application in motion sensors.