Disclosed is a method, device, and system for testing the static contact angle of reagent asphalt, the method includes the following steps: acquiring a side image of a stable droplet formed by a test reagent on asphalt surface, and determining the position of a baseline in the side image; cropping the side image to obtain a droplet image, and extracting droplet contour points in the droplet image; screening out effective contour points corresponding to contours of the two sides of the droplet from the droplet contour points; performing cubic polynomial fitting on the effective contour points to obtain curve function of contour curves on both sides; calculating contact angle value from the curve function and the position of the baseline. The beneficial effects of this disclosure are: this disclosure reduces the difficulty of fitting of the droplet contour and thus improves the calculation precision of the contact angle.

An apparatus and method for coating an electrode slurry are disclosed herein. In some embodiments, the apparatus includes a coater configured to coat an electrode slurry on a metal foil, a measuring unit is configured to measure a remaining oil level on a surface of the metal foil before the coater coating the electrode slurry, and a controller configured to control the coater to coat the electrode slurry based on a measurement value of the remaining oil level of the surface of the metal foil.

A device for detecting a geometry of a drop arranged on a sample surface includes a metering apparatus comprising a liquid reservoir and an outlet opening and a plurality of light sources configured to direct light onto a surface of the drop of liquid. A camera is configured to detect a reflection of the light from the surface of the drop of liquid. The device includes a housing including a recess that forms a cavity that is configured to be separated from external surroundings when the housing is arranged on the sample surface. The plurality of light sources are arranged in the cavity and cover a solid angle of at least π/2 sr when viewed from a point on the sample surface. At least a portion of the metering apparatus is positioned inside the cavity.

A method for analyzing an interaction between a sample surface and a drop of liquid comprises applying the drop of liquid to the sample surface and illuminating the drop of liquid using at least two light sources. The at least two light sources are each arranged at a light source position surrounding the drop of liquid. Light reflected from the drop of liquid detecting and a sensor position on a sensor of a camera is determined for each detected light reflection. Light source positions are assigned to individual light source positions. A position of the drop of liquid is calculated relative to the sensor and an item of size information of the drop of liquid is determined. The position and the item of size information are calculated from the pairs of one sensor position and one associated light source position.

Methods of evaluating viscous compositions are disclosed. The methods may be used to evaluate degradation levels of lubricants including grease. The methods may include preparing a surface for testing by leveling and flattening a viscous composition, placing a drop of a liquid on the flattened leveled surface, evaluating the observed contact angle between the drop and the surface, and then comparing the observed contact angle to a reference contact angle.

A method and testing apparatus determine receding contact angles of liquids on surfaces by depositing a liquid in a manner whereby the volume of the drop is increased through stepwise addition of smaller drops. Each increment of volume growth causes the perimeter of the drop to advance across the surface. The incremental volume elements impart sufficient energy to the growing drop such that the drop perimeter expands beyond its equilibrium diameter for that volume. The drop perimeter tends to contract between volume additions as the excess energy is dissipated. The method and testing apparatus determine the receding contact angle between the incremental volume additions.

Various examples are provided related to determination of contact angle of sessile drops. In one example, a method includes determining a volume of a sessile drop of fluid disposed on a test surface; determining a height of the sessile drop of fluid; and determining a contact angle of the sessile drop of fluid based upon the volume and the height of the sessile drop. In another example, a system includes a volume sensing, a height sensing, and computing that can determine a volume and height of a sessile drop using volume and height data from the sensing, and determine a contact angle of the sessile drop with the volume and the height. The contact angle and surface tension can be determined with at least three of volume, a height, a footprint radius, a radius of maximum horizontal extent, and/or an apex radius of curvature of the drop.

Systems, methods, and computer program products for measurement of surface properties using a mobile device are described, the surface properties including interfacial (surface) tension, contact angle (static, advancing, or receding), solid surface energy, and rolling or sliding angle on an inclined surface. The system has a support adapted to receive a mobile device with a camera and a processor. A structure is coupled to the support that is adapted to removably receive measurement components. The measurement components are configurable to place a droplet or a bubble within a field of view of the camera. Software on the mobile device is configured to operate the camera to take an image of the droplet or the bubble within the field of view of the camera, and to determine one or more physical properties of the droplet or the bubble based on an analysis of the image.

Aspects of the invention include determining, by a first AFM tip, a first snap-off force of a solid surface immersed in a first fluid, determining, by a second AFM tip, a second snap-off force, determining, by a third AFM tip, a third snap-off force, determining, by the first AFM tip, a fourth snap-off force of a droplet of the first fluid immersed in the second fluid on the solid surface, determining, by the second AFM tip, a fifth snap-off force, determining, by the third AFM tip, a sixth snap-off force, determining a first capillary force for first AFM tip and first droplet based on first snap-off force and fourth snap-off force, determining a second capillary force for second AFM tip and first droplet and a third capillary force for third AFM tip and first droplet, and determining interfacial tension between first fluid and second fluid based on the capillary forces.

A testing device determines the presence of substances on a surface using a sensor positioned at a known vantage point to the surface. A liquid dispenser deposits a liquid drop on the surface. A data generator after a first time interval for allowing the liquid drop to stabilize on the surface detects, via the sensor, a geometric characteristic of the liquid drop that is related to a first equilibrium contact angle of the liquid drop to the surface. The data generator after a second time interval detects via the sensor the geometric characteristic of the liquid drop that is related to a second equilibrium contact angle. The data generator compares the first and second contact angle and determines a contamination on the surface that is soluble in the liquid drop in response to a change between the first and second contact angles.