The effect of blob size in polymer networks on the nanoparticle-mediated adhesion hydrogels
Silica nanoparticles can be used as an adhesive for hydrogels or biological tissues due to the physical adsorption to polymer chains. Recently, we found that mesoporous nanoparticles were able to enhance the adhesion energy between hydrogels with 400% of swelling ratio comparing with non-porous nanoparticles because of the higher outer surface area of mesoporous silica nanoparticles. Furthermore, mesoporous nanoparticles with larger pore diameter showed significantly higher nanoparticle-mediated adhesion energy between hydrogels when total outer surface area is comparable. Here, we have changed the swelling ratio of hydrogels in preparation step so that blob size in the polymer network was changed accordingly. In adhesion experiments, we found that the optimum pore size of mesoporous nanoparticles increased as the blob size increased for higher swelling ratio, which is ascribed to the larger blob size of polymer networks in hydrogels.