Spreading of Liquid Drops over Dry Porous Layers: Complete Wetting Case

Surface forces action in a vicinity of three phase contact line and other current problems in kinetics of wetting and spreading

“…The constancy of the contact angle on this stage has nothing to do with hysteresis of the contact angle: there is no hysteresis in our system. These conclusions again are in the good agreement with experimental observations [38] (Figs. 14, 15).…”

“…The predicted theoretical relationships are two universal curves accounting quite satisfactory for the experimental data. According to the theory predictions [38] (i) the dynamic contact angle dependence on the same dimensionless time as before should be a universal function; (ii) the dynamic contact angle should change rapidly over an initial short stage of spreading and should remain a constant value over the duration of the rest of the spreading process. The constancy of the contact angle on this stage has nothing to do with hysteresis of the contact angle: there is no hysteresis in our system.…”

“…As a result of these two competing processes the radius of the drop goes through a maximum value over time. A system of two differential equations has been derived to describe the evolution with time of radii of both the drop base and the wetted region inside the porous layer [38]. This system includes two parameters, one account for the effective lubrication coefficient of the liquid over the wetted porous substrate, and the other is a combination of permeability and effective capillary pressure inside the porous layer.…”

“…Experiments were carried out on the spreading of silicone oil drops over various dry microfiltration membranes (permeable in both normal and tangential directions) [38].…”

Tissue engineering scaffold electrospun from poly(ε- caprolactone)-b-poly(sulfobetaine methacrylate) block copolymers with improved hydrophilicity and good cytocompatibility

“…The evolution of contact angle depends on two major processes, namely, absorption and spreading. Spreading is usually faster than absorption, which mainly affects the starting shape of the droplet [36,37]. Because of the incorporation of hydrophilic SBMA segment, percolation can take place through pores or capillary tubing in PCL-PSBMAs non-woven fabrics, and the value of water contact angle decreased as the absorption processed.…”