RT Journal Article ID 53aa7b343fe205e0 A1 Ravi, Vishaul A1 Jog, Milind A. A1 Manglik, Raj M. T1 EFFECTS OF PSEUDOPLASTICITY ON SPREAD AND RECOIL DYNAMICS OF AQUEOUS POLYMERIC SOLUTION DROPLETS ON SOLID SURFACES JF Interfacial Phenomena and Heat Transfer JO IPHT YR 2013 FD 2014-01-10 VO 1 IS 3 SP 273 OP 287 K1 spray drop-coating K1 non-Newtonian drops K1 drop-spread film AB The postimpact spreading and recoil behavior of millimeter-size liquid droplets of pure water, water−glycerol solution, and non-Newtonian aqueous solutions of medium-grade hydroxyl ethyl cellulose (HEC 250 MR) on dry horizontal hydrophobic (Teflon) and hydrophilic (glass) substrates is presented. The drop spread−recoil dynamics are captured using a high-speed high-resolution digital video recording and image processing. The non-Newtonian effects of aqueous polymeric solutions on postimpact spreading are contrasted with those for a water−glycerol solution with identical surface tension and zero-shear rate viscosity. For a broad range of drop Weber numbers (20 ≤ We ≤ 200), dynamic visualized records of impact, spreading, and recoil are presented along with their measured temporal variations in drop-diameter-scaled spread and film height. The shear-rate-dependent viscosity of the polymer solution is found to give rise to highly complex spread−recoil dynamics compared to Newtonian liquids. During initial spread, because the shear rate tends to be high, shear-thinning or pseudoplasticity effects manifest in polymer solution drops to alter their spread dynamics. Contrarily, during recoil their higher low-shear apparent viscosity tends to retard recoil and dampen shape oscillations. Shear-rate-dependent non-Newtonian behavior is further seen at low We (low shear rate during spreading), where the maximum spread of HEC solution droplets is comparable to that of high-viscosity water−glycerol solution, whereas at high We (high shear rate during spreading), their maximum spreads are closer to those of low-viscosity water droplets. PB Begell House LK https://www.dl.begellhouse.com/journals/728e68e739b67efe,68a304a000484a4c,53aa7b343fe205e0.html