Real-time interferometric monitoring of the dip coating process is applied to the study of properties of flowing liquids. Nonvolatile Newtonian oils are considered, allowing validity of a simple model after the steady state is reached where film physical thickness depends on time as t^-½. Measurement of two distinct mineral oil standards, under several withdrawing speeds, resulted in kinematic viscosities of 1.17 ± 0.03 and 9.9 ± 0.2 S (1S = 1 cm^2/s). Agreement of these results with nominal values from the manufacturer suggests that interferometric monitoring of dip coating may become a valuable method for accurate, contactless viscometry of liquid films. Advantages and present limitations are discussed.
© 2005 Optical Society of America
Alexandre F. Michels, Thiago Menegotto, and Flavio Horowitz, "Optically monitored dip coating as a contactless viscometry method for liquid films," Appl. Opt. 44, 912-915 (2005)