Compositional Dependence of Polyacrylamide Hydrogel Abrasive Wear Resistance

Abstract

The structural and mechanical resemblance of hydrogels to cartilage makes them promising candidates for cartilage replacement in load-bearing joints. As with any sliding interface under high loads, the hydrogels in this application would be highly susceptible to wear. Although the fluid component of these biphasic materials mediates low-friction sliding, the hydrophilic polymer network of hydrogels can endure only a limited number of sliding cycles. In this work, a sandpaper-covered probe attached to a microtribometer with a reciprocating stage was used to wear polyacrylamide hydrogels with varying concentrations of polymers and cross-linkers. The wear volumes and surface features of the resulting wear scars were measured using a 3D laser scanning confocal microscope. The roughness of the wear scars and the friction coefficients during wear application increased with increasing cross-linker concentration. We calculated the wear rates for the different compositions and developed a relationship that connects the polymer and cross-linker concentrations to the wear rates. The wear rate scaled with the polymer concentration to the −2 power and with the cross-linker concentration to the 3/2 power. These results suggest that network flexibility through decreasing cross-linkers and network strength through increasing polymers are key elements of a hydrogel to reduce wear. With this relationship between the hydrogel composition and wear resistance, we can better predict the lifespan of hydrogels in different sliding applications and improve their design to be more resilient.

Eu3+- and Tb3+-Based Coordination Complexes of Poly(N-Isopropyl,N-methylacrylamide-stat-N,N-dimethylacrylamide) Copolymer: Synthesis, Characterization and Property

“…For more than a decade, the application scope of polyacrylamide (PAm) and its derivatives, such as N-substituted and N,N-disubstituted PAms (N-PAms and N,N-PAms, respectively), has rapidly expanded to the fields of biomedical applications, including plastic and reconstructive applications [18,19], contact lenses [20,21], nucleic acid and protein separation [22,23], and drug delivery [24,25]. In addition, the use of PAm as a polymer matrix to synthesize luminescent polymer-rare earth complexes can fully combine the water solubility and thermoresponsive properties of PAm with rare earth ions, to improve their fluorescence properties [26][27][28][29].…”

Impact of Tribological Conditions on Collagen Coating Self-Healing

“…As shown in Figure 6d, it can be seen that the collagen fibers were completely broken, and the collagen coating was torn off, leaving severe wear tracks. Even if the normal load was greatly reduced and the contact pressure condition was alleviated, it can be judged that the collagen fibers were permanently damaged if the number of sliding cycles was high [28]. After applying a normal load of 20 mN to the collagen coating to further alleviate t contact pressure condition, a sliding friction motion was performed.…”

Interfacial Wrinkling Structures Based on a Double Cross-Linking Strategy Enable a Dual-Mode Optical Information Encryption

“…Wear Resistance Test. 29 The sample was fixed on a selfconstructed reciprocating platform, and the surface of the sample was contacted with a 400-grit sandpaper. Then, a load of approximately 5 mN was applied to the reciprocating platform.…”