Contact area

About: Contact area is a research topic. Over the lifetime, 12358 publications have been published within this topic receiving 256401 citations. The topic is also known as: contact patch & contact region.

The effect of polymer surface on the wetting and adhesion of liquid systems

Abstract: Young's equation describes the wetting phenomenon in terms of the contact angle between a liquid and a solid surface. However, the contact angle is not the only parameter that defines liquid–solid interactions, an additional parameter related to the adhesion between the liquid drop and the solid surface is also of importance in cases where liquid sliding is involved. It is postulated that wetting which is related to the contact angle, and interfacial adhesion, which is related to the sliding angle, are interdependent phenomena and have to be considered simultaneously. A variety of models that relate the sliding angle to the forces developed along the contact periphery between a liquid drop and a solid surface have been proposed in the literature. Here, a modified model is proposed that quantifies the drop-sliding phenomenon, based also on the interfacial adhesion that develops across the contact area of the liquid/solid interface. Consequently, an interfacial adhesion strength parameter can be defined dep...

Method to account for true contact area in soda-lime glass during nanoindentation with the Berkovich tip

Abstract: An empirical relationship for estimating the pile-up contact area from the contact stiffness, S and the contact depth, hc, has been developed. This was achieved first by using the atomic force microscope to image nanoindents made with the Berkovich indenter in soda-lime glass and approximating the pile-up contact perimeter as a semi-ellipse. Then, by determining the pile-up contact area for several peak indentation loads, a correlation was found between the pile-up contact area and the load used to generate it. The importance of this new method of determining the pile-up contact area is that the need for indent imaging is made completely redundant, since the contact stiffness is a quantity that is routinely obtained during nanoindentation data analysis. Elastic modulus of soda-lime glass of 70 ± 1.5 GPa is measured with loads ranging from 20 to 500 mN. The hardness measured also falls within the range of values, 5.2–5.9 GPa, normally quoted in the literature for the glass.

Sliding friction of graphene/hexagonal -boron nitride heterojunctions: a route to robust superlubricity.

Abstract: The origin of ultra-low friction exhibited by heterogeneous junctions of graphene and hexagonal boron nitride (h-BN) is revealed. For aligned interfaces, we identify a characteristic contact size, below which the junction behaves like its homogeneous counterparts with friction forces that grow linearly with the contact area. Superlubricity sets in due to the progressive appearance of Moire patterns resulting in a collective stick-slip motion of the elevated super-structure ridges that turns into smooth soliton-like gliding with increasing contact size. Incommensurability effects are enhanced in misaligned contacts, where the friction coefficients further drop by orders of magnitude. Our fully atomistic simulations show that the superlubric regime in graphene/h-BN heterostructures persists up to significantly higher loads compared to the well-studied twisted homogeneous graphene interface. This indicates the potential of achieving robust superlubricity in practical applications using two-dimensional layered materials heterojunctions.