Underwater and wet adhesion
Maintaining an adhesive’s performance underwater is challenging but necessary for many biomedical, military, transportation, and electronics applications. Therefore, understanding how environmental conditions influence the mechanisms of bonding and debonding is essential. In addition, the presence of water alters interactions between intervening surfaces. Our group has the key expertise to study the fundamentals of adhesion to aid in the development of novel chemistry for soft or structural adhesives. We also investigates how physical aspects such as surface topography, elasticity, and hydrodynamics impact contact formation and adhesion.
a) Pressure sensitive adhesives
b) Bonding between polymers and inorganic surfaces
c) Hydrodynamic and contact formation
a) Pressure sensitive adhesives
A pressure-sensitive adhesive (PSA) adheres to a surface once a light external pressure is applied, and can be designed to debond without leaving a residue on the surface. Their simplicity and ease of use make PSAs ubiquitous in everyday life (e.g., consider Scotch tape and Post-it notes). In addition, PSAs are also present in electronics and in medical items, such as wound dressings and drug-delivery patches. Water can affect the adhesive properties of PSAs in different ways. For example, the bulk viscoelastic properties of a PSA can change upon water absorption. In addition, water can also lead to reorganization of the functional groups at the solid-liquid interface. Finally, for efficient bonding under water, the fluid has to be displaced from the gap and crevices separating the surfaces. Therefore, a better understanding of the role of an aqueous environment on the bonding and debonding processes of PSAs is necessary.
- P. Karnal, A. Jha, H. Wen, S. Gryska, C. Barrios, and J. Frechette, “Role of acrylic acid co-monomer on the underwater adhesion of acrylic pressure sensitive adhesives”, Langmuir, 35, 5151-5161, 10.1021/acs.langmuir.9b00120
- P. Karnal, P. Roberts, S. Gryska, C.L. King, C. Barrios, and J. Frechette, “Importance of substrate functionality on the adhesion and debonding of a pressure sensitive adhesive under water”, ACS Applied Materials & Interfaces, 9, 42344-42363, 2017.
b) Bonding between polymers and inorganic surface
Understanding fundamental principles of adhesion between polymers and inorganic surfaces in various media is of interest in the areas of elastomeric adhesives, structural adhesives, hybrid material interfaces, and composite material interfaces. All of these areas require materials to perform well in extreme dynamic environments that include high strain rate impact events, and/or dynamic environmental conditions (high and low humidity and temperatures). Fundamental characterization and understanding of these interfaces is necessary in the development of novel polymer chemistry.
Bonding at polymer -inorganic interface
Voids created by the presence of water in polymer
- Pick, C. Argento, G. Drazer, and J. Frechette, “Micropatterned Charge Heterogeneities via Vapor Deposition of Aminosilanes”, Langmuir, 31,10725-10733, 2015. 10.1021/acs.langmuir.5b02771
- “Template stripped Aluminum film for the Surface Forces Apparatus”, to be submitted.
c) Elasticity and hydrodynamics
Forces caused by the relative movement of two surfaces in a viscous fluid can exert local pressures that can be sufficiently large to cause elastic deformation of the interacting materials. Such a situation occurs during the drainage or infusion of fluid in a confined gap, where the presence of an elastic boundary can lead to elastohydrodynamic deformation. Elastohydrodynamic deformation plays an important role in soft matter where materials such as gels, biological tissues, or elastomers (Young’s modulus ~ 10 kPa-10 MPa) can deform during motion in a fluid at relatively low velocities and viscosities. We aim to better understand how the coupling between viscosity and elasticity impacts contact formation and adhesion.
- M. Tan, Y. Wang, and J. Frechette, “Criterion for particle rebound during wet collisions on elastic coatings”, Physical Review Fluids, 4, 084305, 2019. 10.1103/PhysRevFluids.4.084305
- Y. Wang and J. Frechette, “Morphology of soft and rough contact via fluid drainage”, Soft Matter 14, 7605-7614, 2018. 10.1039/C8SM00884A
- Y. Wang, M. R. Tan, and J. Frechette, Elastic deformation of soft coatings due to lubrication forces, Soft Matter, 13, 6718-6729, 2017. 10.1039/C7SM01061C
- Y. Wang*, G. Pilkington*, C. Dhong, and J.Frechette, “Elastohydrodynamic deformation of soft materials during dynamic surface forces measurements”, Current Opinion of Colloid and Interfacial Science, 27, 43-49, 2017. 10.1016/j.cocis.2016.09.009
- Y. Wang, C. Dhong, and J. Frechette, “Out-of-contact deformation due to lubrication forces”, Physical Review Letters, 115, 248302, 2015.10.1103/PhysRevLett.115.248302
- C. Dhong and J. Frechette, “Coupled effects of applied load and surface structure on the viscous forces during peeling”, Soft Matter, 11, 1901-1910, 2015. 10.1039/C4SM02616K