Optical Fiber Glass Tip for Cantilever Based Optical Interfacial Force Microscope in Liquid
Application of Cantilever Based Optical Interfacial Microscopy (COIFM) in an aqueous environment is important in understanding how various interactions depend on the distance between two surfaces, such as colloidal particles. Because of COIFM’s electrical signaling for force-feedback it has difficulty probing aqueous interactions. To avoid disastrous electrochemical reactions, the sensor must be isolated from liquids. Through an optical fiber tip long enough to penetrate the fluid, produced via laser-based method, the cantilever remained safely suspended above the liquid. The sensor has been characterized testing the systems bandwidth in air and is measured to be ~516 Hz (one twentieth of the bare COIFM sensor). The force sensor has been demonstrated in aqueous environments, in which the force-distance curves clearly shown hydration repulsion between two silica surfaces.