Premium
Injectable and moldable hydrogels for use in sensitive and wide range strain sensing applications
Author(s) -
Qiao Zhen,
Mieles Matthew,
Ji HaiFeng
Publication year - 2020
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.23355
Subject(s) - self healing hydrogels , gelatin , polyacrylamide , ultimate tensile strength , gauge factor , chemistry , strain (injury) , composite material , materials science , chemical engineering , polymer chemistry , fabrication , biochemistry , alternative medicine , pathology , medicine , engineering
Abstract Recently, the use of hybrid double network (DN) hydrogels has become prominent due to their enhanced mechanical properties, which has opened the door for new applications of these soft materials. Only a few of these gels have demonstrated both injectable and moldable capabilities. In this work, we report the mechanical properties, gauge factor (GF) values and demonstrate both the injectability and moldability of a gelatin/polyacrylamide DN hydrogel. We optimized several parameters, such as, gelatin to polyacrylamide ratio, reactant concentrations and metal ion concentration, to produce a gelatin/polyacrylamide hydrogel with superior mechanical properties. The highest water content gel was capable of withstanding strains of 5000% before failure. These gels were facilely injected into molds where they effectively changed shape and maintained similar properties prior to remolding. When 20 mM calcium was doped into a similar gel, a tensile strength of 1.71 MPa was achieved. Aside from improving the mechanical properties of the gels, both Ca 2+ and Mg 2+ also improved their conductivity, so they were tested for use as strain sensors. The sensitivity of the hydrogel strain sensors were measured using the GF. For the 20 mM Ca 2+ hydrogel, these GF values ranged from 1.63 to 6.85 for strains of 100% to 2100% respectively. Additionally, the sensors showed good stability over continuous cyclic stretching, demonstrating their long term reliability for strain sensing.