화학공학소재연구정보센터
Journal of Chemical Engineering of Japan, Vol.43, No.1, 40-45, 2010
Nonuniform Thinning of Polymeric Coatings under Marangoni Stress
We investigate the surface deformation of polymeric coatings dried under interfacial stresses. The surface-tension-driven Marangoni stress drives the liquid from low-surface-tension regimes to high-surface-tension regimes. The results of our computations reveal that with an increase in the Biot number, three distinct deformation modes are formed: (i) one elevation and two depressions, (ii) flat interface, and (iii) one depression near the air impingement point. A new drying map is presented to show the manner in which the nonuniform thickness varies with the Biot and Marangoni numbers. The map helps us decide the optimum operating conditions for achieving uniform surface coatings.