|About this Abstract
|2023 TMS Annual Meeting & Exhibition
|Frontiers of Materials Award Symposium: Functional Composition Control of Surface Mechanics in Soft, Water-swollen Gels
|Friction of Thin Hydrogel Films: Disentangling the Contributions of Poroelastic Flow and Interface Molecular Interactions
|On-Site Speaker (Planned)
Friction of water-swollen hydrogels involves a complex interplay between poroelastic flow, elasto-hydrodynamic lubrication and molecular interactions at the contact interface. Here, these issues will be discussed from contacts experiments between model hydrogel thin (~ Ám) films grafted on silicon substrates and silanized glass probes, in situations where elasto-hydrodynamic lubrication is prevented. From a combination of dedicated linear sliding and rotational friction experiments with in situ contact visualization, we show that the main contribution to friction of poroelastic flow within the bulk polymer network arises from velocity-dependent changes in the contact geometry. Most of the frictional energy dissipation is found to result from interface effects which are discussed using a modified form of the Schallamach’s model taking into account molecular pinning-depinning events at the glass/gel interface. This approach provides a consistent description of the friction force when the velocity, the normal force and the physical chemistry of the glass probe are varied.
|Planned: None Selected