| 摘要 |
<p>The invention relates to an apparatus for determining by optical means the contact angle (wetting angle) at the solid-liquid interface, allowing the hydrofobicity of some materials to be studied and estimated and the surface pressure to be determined in research activities, in industry, and in particular in textiles, plastics, dyestuffs industries etc., as well as in agriculture. The apparatus comprises an optical measuring unit (A) mounted in front of a sample-holding device (B), on a base plate (C). The optical unit (A) comprises a horizontal axis objective (4), a 90 reflecting prism (5) and an eyepiece (6) integral with a cross reticle (7) ensuring a magnification of 50-100 times of the image of a liquid drop (2) on a sample (1) placed on a mobile table (18) of the sample-holding device (B), having three mobility degrees and a mobile mirror (30) for the adequate illumination of the liquid drop (2). The size of the contact angle (alpha) is determined either directly, by measuring on an instrument dial (14) in correspondance with an indicating pointer (13), or indirectly, by trigonometric calculation, after the previous measurment of the diameter "D" and height "H" of the liquid drop (2).</p> |
