3D Printing of Stretchable, Adhesive and Conductive Ti3C2Tx-Polyacrylic Acid Hydrogels

Abstract

Stretchable, adhesive, and conductive hydrogels have been regarded as ideal interfacial materials for seamless and biocompatible integration with the human body. However, existing hydrogels can rarely achieve good mechanical, electrical, and adhesive properties simultaneously, as well as limited patterning/manufacturing techniques posing severe challenges to bioelectronic research and their practical applications. Herein, we develop a stretchable, adhesive, and conductive Ti3C2Tx-polyacrylic acid hydrogel by a simple pre-crosslinking method followed by successive direct ink writing 3D printing. Pre-polymerization of acrylic acid can be initiated by mechanical mixing with Ti3C2Tx nanosheet suspension, leading to the formation of viscous 3D printable ink. Secondary free radical polymerization of the ink patterns via 3D printing can achieve a stretchable, adhesive, and conductive Ti3C2Tx-polyacrylic acid hydrogel. The as-formed hydrogel exhibits remarkable stretchability (~622%), high electrical conductivity (5.13 S m−1), and good adhesion strength on varying substrates. We further demonstrate the capability of facilely printing such hydrogels into complex geometries like mesh and rhombus patterns with high resolution and robust integration.

Low Hysteresis and Fatigue-Resistant Polyvinyl Alcohol/Activated Charcoal Hydrogel Strain Sensor for Long-Term Stable Plant Growth Monitoring

“…The AC particles settle by gravity in the solution, and the viscosity of the PVA solution prevents the settling rate of the AC particles until the AC particles maintain equilibrium. The rheological characterization of the PVA-AC conductive hydrogel inks demonstrates that the viscous PVA solution facilitates the conductive AC to disperse ( Figure 1 b) [ 26 , 27 , 28 ]. The continuous conductive network eliminates the tunneling effect between the conductive particles and the substrate material, effectively minimizing hysteresis during the stretching process.…”

Challenges of Periodontal Tissue Engineering: Increasing Biomimicry through 3D Printing and Controlled Dynamic Environment

“…To avoid the functionalization through bio-active molecules, increasing interest in the synthesis of conductive polymers that are also printable—such as poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) [ 109 ], which can be conveniently enriched by poly(vinyl alcohol) (PVA) forming a hydrogel strain sensor [ 110 ]—has been conveyed. Conductive hydrogels may become ideal interfaces with the human body, but rarely simultaneously possess the satisfying electrical, mechanical, and adhesive properties shown by the Ti3C2Tx-polyacrylic acid hydrogel that can be printed into complex geometries with high resolution [ 111 ].…”

3D Printing of pH Indicator Auxetic Hydrogel Skin Wound Dressing

“…The colorimetric appearance of the hydrogel changed with pH, and the absorption peak positions were correlated to the pH ranges. However, these studies [ 2 , 10 , 11 , 12 , 13 , 14 ] did not disclose the drainage capability of the dyes from the hydrogel matrix. This is an important aspect because the entrapment only occurred on the surface of the wound dressing, which causes dye leakage when they come in contact with excess exudates.…”

“…They snapped the printed hydrogel and reattached it to the body’s original form to test the PAA’s adhesion capability. Zhao et al [ 12 ] additively manufactured a stretchable and highly adhesive Ti 3 C 2 Tx-PAA hydrogel using ink writing 3D printing. They demonstrated the adhesion capability on various materials, such as glass, metal, PTFE, and pigskin, with different concentrations of Ti 3 C 2 Tx and PAA, and it was found that increasing the concentration of PAA enhanced the adhesion strength significantly.…”