Medidas de tensão superficial pelo método de contagem de gotas: descrição do método e experimentos com tensoativos não-iônicos etoxilados

Abstract

Recebido em 11/2/08; aceito em 7/7/08; publicado na web em 10/12/08 SURFACE TENSION MEASUREMENT BY DROP COUNTING METHOD: METHOD DESCRIPTION AND EXPERIMENTS WITH ETOXILATED NON-IONIC SURFACTANTS. Surface tension knowledge of surfactants aqueous solutions is important during amphiphilic molecule manufacturing and new product development, as feedback information to handle synthesis parameters to target performance. Drop counting method is an interesting simplification of drop weight method for surface tension measurements. A simple laboratory measurement device, with capability for temperature control, was assembled to allow investigation of ethoxylated surfactants. The implementation of the method was preceded by a detailed investigation of two factors that may affect the measured surface tension: drop formation velocity and surfactant ethoxylation degree. The limitations of the method are discussed on this basis.