Development of a facility for Axisymmetric Drop Shape Analysis-profile (ADSA-P)

Axisymmetric Drop Shape Analysis (ADSA) is a computer software package deve loped in our laboratory [1-8]. It uses digital image analysis to detect the edge of a drop and determines a number of surface parameters including the interfacial tension gamma and contact angle theta. The measurement of thes e quantities is essential to the study of Surface Thermodynamics, and ADSA is capable of determining these parameters with greater accuracy and flexib ility than traditional techniques. The software has been refined continuous ly over a fifteen-year period; however, the hardware had not evolved signif icantly, and thus remained an improvised collection of parts that was often difficult to use. To remedy this situation an improved facility was design ed and built, one which allows the experimentalist to measure more easily a nd accurately both interfacial tensions and contact angles using ADSA. The design is capable of handling a wide variety of systems and experiments, in cluding the measurement of interfacial tension [1, 5, 6, 8, 9], line tensio n [1, 10-12], film tension [1, 13, 14], surface pressure [1, 15, 16], surfa ce dilational modulus [1], surface dilational viscosity [1], and contact an gles for liquid-fluid systems [1, 2-7]. It also allows these experiments to be conducted under variable conditions, such as high pressure and temperat ure. This work discusses the development of both the basic facility and Mot orized Syringe (MOS) which allows the drop volume to be manipulated.