Study on stick-slip vibrations of gelatin hydrogel in dry and wet conditions

Abstract

High deformability, softness, adhesiveness and swelling ability make hydrogels highly suitable for biomedical and pharmaceutical applications like tissue regeneration, drug delivery system, wound dressing and plastic surgery. Direct shear sliding experiments are conducted on gelatine hydrogel using low velocity linear tribometer under the dry conditions and in presence of water. Sliding experiments are conducted for 10% concentration at sliding velocities of 0.075 to 0.1 mm/sec at normal stresses of 0.613–1.839 KPa. Interfacial frictional shear stress (ι) of the sliding interfaces is measured using Slide-Hold-Slide experiments in stick–slip regime. Effects of sliding velocity(v), normal stress (σn) and the lubrication medium on shear stress, stick–slip behaviour and frequency are studied in detail. Presence of water at the interface reduces the shear stress substantially for all the velocity ranges. Frequencies of stick–slip cycles were relatively higher in presence of water when compared to that of dry condition. Increase in the normal stress leads to decrease in the vibration frequency of stick–slip cycles.