A 360-degree contact angle goniometer is a precision optical instrument used to measure the contact angle between a liquid droplet and a solid surface. This measurement provides crucial information about the wettability, surface energy, and surface tension of materials, which is fundamental in surface science and materials characterization. This goniometer typically employs a sessile drop method, where a liquid droplet of a predefined volume (e.g., a few microliters) is dispensed onto the surface. High-resolution cameras capture images or video of the droplet, often at high frame rates (e.g., 80 images per second or up to 30 frames per second), allowing for both static and dynamic contact angle measurements. The "360-degree" aspect can refer to the ability to measure angles around the entire droplet or to a goniometer head that allows full rotation for comprehensive analysis. Specifications include camera resolution (e.g., 1920x1080 pixels), syringe volume (e.g., 25 µl), and needle diameter. Automated systems often feature motorized stages for precise X, Y, and Z axis movement, and sometimes rotation, to position the sample and focus the camera. Contact angle goniometers are indispensable in various scientific and industrial applications, including the development of coatings, adhesives, and lacquers, where understanding wetting properties is critical for performance. They are used to assess surface cleanliness, the efficacy of surface treatments, and to study phenomena like spreading, absorption, and adhesion. In biomimetic surface engineering, goniometers help characterize surfaces designed for specific wetting behaviors, such as superhydrophobicity or superhydrophilicity, which are inspired by natural surfaces. They are also used to determine surface free energy and interfacial tension. Advanced goniometers come with sophisticated image analysis software that automatically detects contact points, calculates contact angles, and provides data on surface tension and surface free energy. Features like automated injection systems, temperature control, and environmental chambers allow for measurements under controlled conditions. Some models offer dynamic measurements, such as advancing and receding contact angles, or tilting plate methods, which provide insights into surface heterogeneity and hysteresis. Portable versions are also available for quality control applications.