Four-petal aqueous imbibition into woven cloth

Abstract

HypothesisImproving the processing efficiency of aerosol-coating technologies during mass production requires optimal nozzle spacing to allow complete surface coverage while at the same time not over-using the coating fluid. The difficult challenge is to estimate quantitatively the substrate coverage of fine droplets. Bouncing, splashing, and imbibition of droplets on solid surfaces have been widely explored, but little attention has been paid to liquid imbibition into woven textiles. ExperimentsHere, we experimentally and theoretically study the imbibition dynamics of aqueous droplets on woven cloths. The experimental process was observed using magnified visual observation. A proposed continuum mathematical model well predicts the aqueous imbibition fronts as a function of time. FindingsA captivating four-petal imbibition spreading pattern is observed at enhanced magnification. The imbibition occurs separately in the megapores of the cloth between yarns, and in smaller minipores within individual yarn bundles. Surprisingly, weave intersections do not allow cross imbibition accentuating an anisotropic imbibition pattern. The proposed model achieves quantitative agreement with experiment. This is the first time that the mechanisms of four-petal droplet deposition, spreading, and imbibition into woven cloth have been outlined and successfully simulated. The mathematical model predicts advancement of liquids in anisotropic woven cloth, and permits evaluation of the coverages of droplet spreading.