Improved adhesion between glass fiber and <scp>PAAm</scp> / <scp>SA</scp> hydrogel via a synergy strategy

Abstract Fiber‐reinforced hydrogels remain mechanically inferior to natural cartilage, primarily due to underexplored design issues at the matrix‐fiber interfaces. In this study, a synergy strategy combining chemical bonding, topology of connection, and energy dissipation is used to improve the interfacial properties of glass fiber and calcium crosslinking polyacrylamide/sodium alginate (PAAm/SA) double‐network hydrogels. Using γ‐(methacryloyloxy)propyltrimethoxysilane (TMSPMA) as a functional modifier is explored to enhance the chemical bonding between the glass fibers and hydrogels. Interfacial shear strength is quantified through pull‐out tests, revealing a significant improvement after chemical modification. Specifically, TMSPMA‐treated samples exhibit an interfacial shear strength of 28.8 ± 2.3 MPa, compared to 5.5 ± 0.4 MPa for untreated samples. The study further examines the influence of energy dissipation via ionic crosslinking, showing that Ca 2+ crosslinked hydrogels achieved superior interfacial strength (28.8 ± 2.3 MPa), which is 3–4 times higher than that of Ba 2+ and Fe 3+ crosslinked counterparts. Additionally, introducing 2–6 twists to the fiber bundle reduces interfacial strength by ~1.4–1.8‐fold, showing that topology area is also essential to the hydrogel adhesion. These findings contribute to the understanding of interfacial properties between fiber and hydrogel and hold potential for advancing load‐bearing biological substitute designs. Highlights Glass fiber is modified by TMSPMA to increase chemical bonding 2 wt% TMSPMA‐treated samples exhibit a superior interfacial shear strength of 28.8 MPa Higher concentration TMSPMA leads to filled gaps in glass fiber bundles. Ca 2+ crosslinked hydrogels achieved superior interfacial properties compared to Ba 2+ and Fe 3+ Hydrogel adhesion relies on chemical bonds, topology, area, and energy dissipation.