An evaluation of methods for contact angle measurement

A systematic comparison of Wilhelmy-balance tensiometry (WBT), tilting-plate goniometry (TPG) and captive-drop goniometry (CDG), using a variety of silane-treated glass surfaces of variable wetting characteristics is reported. WBT was assumed to be the benchmark of comparison (gold standard). Advancing angles measured by TPG and CDG were in statistical agreement with corresponding WBT measurements. In contrast, receding angles from both goniometric techniques were systematically higher than WBT.