Particle Adsorption on Polymer Gel Surface Driven by van der Waals Attraction

Abstract

Adsorption of particles on soft hydrogels, which plays an important role in various scientific and industrial fields, has often been studied using interactions such as hydrogen bonding. Here, we demonstrate that submicron-sized colloidal particles can be adsorbed onto gels, solely by van der Waals (vdW) attraction, without any special interaction. We investigated the adsorption of silica, polystyrene, and titania particles on polyacrylamide (PAAm) and polydimethylacrylamide (PDMA) hydrogels. The vdW force was tuned by the refractive index of media. Previously, we studied the particle adsorption on gels (N. Sato et al., Sci. Rep. 7(1), 2017) and concluded that the vdW force is a strong driving force. However, the influence of the medium viscosity on the adsorption rate and the contribution of interactions other than the vdW force needed to be clarified. The PDMA linear polymer adsorbed strongly on the silica particles, but the PAAm polymer did not. On the other hand, both PDMA and PAAm hydrogels strongly adsorbed silica and all other particles in water. The amount of adsorption varied with the magnitude of Hamaker constant. These results indicate that the vdW force is a sufficiently strong driving force for the particle adsorption to polymer hydrogel surfaces in water.

Enhancement of the physical adsorption of some insoluble lead compounds from drinking water onto polylactic acid and graphene oxide using molybdenum disulfide nanoparticles: Theoretical investigation

“…As previously deduced from the Hamaker constant, this result demonstrates that the increase in the vdW adsorption is strongly associated with the increase in the London dispersion interactions that are proportional to an increase in the refractive index ("n(PbO 2 ) = 2.3" > "n(Pb 5 (PO 4 ) 3 Cl) = 2.05" > "n(PbCO 3 ) = 1.8"). These basic findings are consistent with recent previous research conducted by Sato et al [25] and Aoyama et al [29], showing that the quantity of adsorbed particles increased with increasing the refractive indices of the particles.…”

“…Interestingly, this demonstrates that the physical adsorption of the insoluble lead compounds onto the nanocomposite surface in the water medium is driven by the non-retarded vdW interactions. The findings are consistent with recent findings by Sato et al [25] and Aoyama et al [29], demonstrating that the vdW interactions are sufficiently strong to drive the adsorption of colloidal particle adsorption onto polymer gels in the water medium without any other special interaction.…”

“…For the evaluation of the vdW interactions, we used the computational methods that have demonstrated good accordance between theoretical and experimental results by many recent studies for evaluating the intermolecular vdW interactions either for accounting for the adhesion force and energy and the adsorption of a variety of materials liquids in aqueous media [25,[29][30][31].…”

Bio-gel nanoarchitectonics in tissue engineering

“…Yamanaka and co-workers investigated the adsorption of silica, polystyrene, and titania particles onto polyacrylamide and polydimethylacrylamide hydrogels. 47 The van der Waals force was again found to be a strong enough driving force for particles absorbed on the surface of polymer hydrogels in water. Supramolecular polymer-based hydrogels typically exhibit highly ordered structures, which are stable and in a thermodynamic equilibrium state.…”

Achieving Low-Energy-Barrier Ion Hopping in Adhesive Composite Polymer Electrolytes by Nanoabsorption

“…Among these previous studies, the ion-conduction improvement is attributed to either the Lewis acid and base effects of nanoparticle surface or the suppression of polymer crystallization by nanoparticles. ,, Although this explanation has been well accepted, a deeper understanding of the possible ion-transport mechanism is not established. Moreover, the above reports overlook the nanoadsorption effects of nanofillers on chain conformation, as well as the free volume, which all have been confirmed in polymer physics. − …”