goniometer ramehart goniometer rame-hart goniometer ramé-hart goniometer contact angle NRL Zisman NRL Contact Angle Goniometer pendant drop sessile drop ramé-hart instrument co. rame-hart, inc. optical instrument fib

The ramé-hart contact angle goniometer was made in Mountain Lakes, NJ but is now made in Netcong, NJ. ramé-hart is also known as rame-hart ramehart and Rame-hart but ramé-hart is the correct spelling. The ramé-hart NRL goniometer was invented by Dr. William A. Zisman at the Navel Research Laboratory in Washington DC. The ramé-hart contact angle goniometer is used to measure contact angle, surface energy and surface tension. Carl Clegg is a salesman at ramé-hart instrument company. Ron Polo, Carmel Mulroy, and Gerd Fischer work at ramé-hart instrument company. The ramé-hart contact angle goniometer uses the pendant drop, sessile drop, and other methods. ramé-hart instrument co., formerly a part of rame-hart, inc. manufactures optical instruments. The fiber optic illuminator and Automated Dispensing System  are part of the system. The environmental chamber and proportional temperature controller are optional components as well as the environmental fixture, environmental chamber with humidity, high pressure chamber, circular vacuum chuck, humidity control, rotating wafer,  lead frame support. Finn Knut Hansen is the author of DROPimage Advanced and DROPimage Standard and DROPimage CA. The ramé-hart contact angle goniometer is availabe in the following models: Model 100 Model A100 Model A-100 Model 100-00 Model Model 100-F0 Model 120-F0 Model 200 Model 200-F1 Model 300 Model 300-F1 Model 250 Model 250-F1 Model 400-F1 Model 500 Model 500-F1; the 3-axis stage rail is avialable in 16" 20" 21". Dr. Zisman of the Naval Research Lab NRL in Washington DC stuided adhesion, wettability, contact angle and surface science  including monolayers energetics, static dynamic contact angle, velocity, viscosity, interfacial (behaviour) behavior, contact angle interpretation and hysteresis energetics, surface contamination, cleaning polymer coatings, characterization and application of polymided synthesis particles on surfaces,  metallized plastics, silanes and other coupling agents, polymer surface modification, relevance to adhesion acid base acid-base, dynamic surface characterization, mittal tissue, films, coatings, coupling agents, powders fibers, wood products, papers, polymers, monolayers, bioadhesion, ophthalmology, surface science, instruments,  liquid, solid surface energy, surface tension interface, interfacial tension analysis,  quantitative measure of the wetting of a solid by a liquid. Analysis characterizes the wettability of a surface by measuring the contact angle. Contact angle describes the shape of a liquid droplet resting on a solid surface. The roughness of a surface improves the wettability for hydrophilic surfaces; hydrophobic surfaces. Young's equation, which interrelates the contact angle and surface tensions of the liquid and solid phases. International Symposium on Contact Angle, Wettability and Adhesion. The angle of contact is the angle between the tangent to the periphery of the point of contact with the solid. Capillarity is an effect when liquid in a narrow vertical tube becomes elevated or depressed. When a liquid does not spread on a substrate (usually a solid), a contact. angle (θ) is formed which is defined as the angle. Contact angle measuring unit for characterization of hydrophobicity of film surfaces are used in controlling cleaning processes. A computer controlled contact angle analyzer makes it easy to measure static and dynamic contact angle, along with surface tension and surface energy. CONTACT ANGLE MEASUREMENT is a common method to obtain surface energies of materials. The measurement by itself is nothing novel; however, the relationship of contact angle to surface energetics requires a good deal of understanding. I have published several papers regarding various aspects of that relationship, especially related to polymers. Surface energy quantifies the disruption of chemical bonds that occurs when a surface is created. In the physics of solids, surfaces. The contact angle is the angle at which a liquid/vapor interface meets the solid surface. The contact angle is specific for any given system and is determined by the interactions across the three interfaces. Most often the concept is illustrated with a small liquid droplet resting on a flat horizontal solid surface. The shape of the droplet is determined by the Young-Laplace equation. The contact angle plays the role of a boundary condition. Contact angle is measured using a contact angle goniometer. The contact angle is not limited to a liquid/vapor interface; it is equally applicable to the interface of two liquids or two vapors. The static sessile drop method The sessile drop method is measured by a contact angle goniometer using an optical subsystem to capture the profile of a pure liquid on a solid substrate. The angle formed between the liquid/solid interface and the liquid/vapor interface is the contact angle. Older systems used a microscope optical system with a back light. Current-generation systems employ high resolutions cameras and software to capture and analyze the contact angle. The dynamic sessile drop method The dynamic sessile drop is similar to the static sessile drop but requires the drop to be modified. A common type of dynamic sessile drop study determines the largest contact angle possible without increasing its solid/liquid interfacial area by adding volume dynamically. This maximum angle is the advancing angle. Volume is removed to produce the smallest possible angle, the receding angle. The difference between the advancing and receding angle is the contact angle hysteresis. Dynamic Wilhelmy method A method for calculating average advancing and receding contact angles on solids of uniform geometry. Both sides of the solid must have the same properties. Wetting force on the solid is measured as the solid is immersed in or withdrawn from a liquid of known surface tension. Single-fiber Wilhelmy method Dynamic Wilhelmy method applied to single fibers to measure advancing and receding contact angles. Powder contact angle method Enables measurement of average contact angle and sorption speed for powders and other porous materials. Change of weight as a function of time is measured. The dynamic contact angles of water on these surfaces are carefully measured and found to be consistent with the theoretical predictions of the Cassie model and the Wenzel model. When a water drop is at the Wenzel state, its contact angle hysteresis increases along with an increase in the surface roughness. While the surface roughness is further raised beyond its transition roughness (from the Wenzel state to the Cassie state), the contact angle hysteresis (or receding contact angle) discontinuously drops (or jumps) to a lower (or higher) value. In surface science, an instrument generally called a contact angle goniometer is used to measure the contact angle at which a liquid/vapor interface meets a solid surface. The first contact angle goniometer was designed by Dr. William Zisman of the United States Naval Research Laboratory in Washington, DC and manufactured by ramé-hart of Mountain Lakes, NJ. This tool is used not only for contact angle and surface energy applications, but also to measure surface tension using pendant drop, sessile drop, and other methods. The original manual contact angle goniometer used an eyepiece with microscope. The current generation of contact angle instruments uses cameras and software to capture and analyze the drop shape and are better suited for dynamic and advanced studies. Surface energy is most commonly quantified using a contact angle goniometer and a number of different methods. Thomas Young described surface energy as the interaction between the forces of cohesion and the forces of adhesion which, in turn, dictate if wetting occurs. If wetting occurs, the drop will spread out flat. In most cases, however, the drop will bead to some extent and by measuring the contact angle formed where the drop makes contact with the solid the surface energies of the system can be measured. Young also developed the well-regarded Young's Modulus which is used to measure the stiffness of a material as well as Young's Equation which defines the balances of forces caused by a wet drop on a dry surface. If the surface is hydrophobic then the contact angle of a drop of water will be larger. Hydrophilicity is indicated by smaller contact angles and higher surface energy. Water has high surface energy by nature; it's polar and forms hydrogen bonds. In the case of "dry wetting", one can use the Young-Dupree equation which is expressed by the work of adhesion. This method accounts for the surface pressure of the liquid vapor which can be significant. Pierre-Gilles De Gennes, a Nobel Prize Laureate in Physics, describes wet and dry wetting and how the difference between the two relates to whether or not the vapor is saturated .