Abstract
A new application of the Langmuir-Adam surface pressure technique has been made in the study of ageing of surface of solutions. It is found that a fresh surface of a solution of benzopurpurin exhibits a fall of surface tension with time. If by suitable methods, an overcrowding (by solute molecules) of the surface is brought about, such a surface exhibits a rise of surface tension in time. The molecules accumulated at the surface are shown to exhibit a reluctance to get into solution; it has therefore been possible to measure the rate of accumulation and has been found to be very slow. The slowness is best accounted for on the basis of activated accumulation. The postulation of activation is further helpful in understanding (a) the time variation of surface tension, (b) the high temperature coefficient and (c) the manifestation of surface pressure. The results of the present investigation are extremely helpful in measuring the efficacy of a substance as the stabiliser of foam. Several new lines of investigation which have opened up are briefly indicated.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
