Nano Surface‐Heterogeneities of Particles Modulate the Macroscopic Properties of Hydrogels

Abstract

AbstractNanoparticles, when incorporated into polymer matrices, can improve the intrinsic properties of composite materials. These materials possess fascinating properties and find widespread applications in bioengineering, medicine, aerospace, and electronics. However, the impact of nanoparticle surface heterostructures on composite systems is not fully understood. To bridge this gap, composite hydrogels (HRCs) are developed using rough‐surfaced raspberry‐like colloidal (RC) particles. It is hypothesized that the surface roughness of nanoparticles can significantly affect their adsorption, motion, and interfacial forces when interacting with polymeric networks, thereby influencing the macroscopic properties of HRCs. The properties of HRCs are compared with those of composite hydrogels containing smooth‐surfaced particles (HSCs) to isolate the effect of surface roughness. The results show that the nano‐surface heterogeneities of nanoparticles dictate the macroscopic properties of HRC hydrogels. It is found that HRCs exhibit much greater mechanical and adhesive properties compared to HSCs and control hydrogel without nanoparticles. As identified by the relaxation behavior, the enhanced frictional drag of interstitial fluid due to surface roughness, combined with the strong interaction of polymer network components dynamically linked by rough‐surfaced RC particles, is responsible for these improvements. These findings can guide the design and fabrication of new nanocomposites, including hydrogels, for various applications.