An Optical Method to Simultaneously Measure Liquid Surface Tension Coefficient and Contact Angle

Abstract

The invention discloses an optical method for simultaneously measuring a surface tension coefficient and a contact angle of a liquid. The optical method utilizes parallel laser beams to vertically illuminate the curved liquid surface. Through change of the position of an observation screen, the reflected light field characteristics of the observation screen at different positions are acquired through an area array microscopy camera and computer image processing. Through a Young-Laplace equation, the curved surface equation of the curved liquid surface is calculated. According to the curved surface equation for respectively solving a surface tension coefficient and a contact angle, the liquid surface tension and a contact angle are simultaneously measured when an unknown liquid to be testedcontacts with a device material. The optical method is easy to operate in a test, realizes non-contact measurement and has non-destructive characteristics and strong operability.

Description

【Technical Field】 [0001] The invention belongs to, and specifically relates to an optical method for synchronously measuring the surface tension coefficient and contact angle of a liquid. 【Background technique】 [0002] Surface tension and contact angle are two important parameters describing fluid properties, and they have important applications in fluid mechanics. There are many methods for measuring the surface tension of liquids. The national standard specifies the flat plate method or the ring method as the standard for measuring the surface tension coefficient [1]. In addition to the method specified by the national standard, the common method for measuring the surface tension coefficient is capillary rise. Method, hanging drop method, drop volume method, maximum bubble pressure method, oscillating jet method, capillary wave method, laser diffraction method, etc. In these surface tension coefficient measurement methods, they all rely on the known liquid contact angle. The...

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Problems solved by technology

At present, the ADSA (Axisymmetric Drop Shape Analysis) algorithm is commonly used to calculate the contact angle. The models established by some new methods can measure the surface tension coefficient and the contact angle at the same time. Such methods are often subject to problems such as large measurement limitations and poor operability. troubled

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