Study of the Droplet Pinning Force in the Transition from Dry to Liquid-Infused Thin Polymer Films

Abstract

The change in the pinning force during the transition from dry to oil-impregnated thin polymer films is studied for droplets of water and hexadecane. A careful variation of the oil amount in the films is performed by means of supercritical impregnation. The film thickness dependence on the oil content is measured using ellipsometry and compared to gel swelling theory estimates. Depending on the oil content, two cases of pinning force behavior have been identified. For each case, the factors that determine the pinning force are discussed. The pinning force in the transition from dry to equilibrium swollen gel films is well approximated by the Joanny and de Gennes hysteresis model of dilute defects.

Dependence of Slippery and Elastic Properties of Thin Polymer Films on the Grafted Flexible Sidechain Amount

“…48,51 It has been shown that the pinning force of the test droplets in the transition from dry to swollen fluorinated polymer matrix is well described by the de Gennes theory of diluted defects. 52 This work was inspired by the result of Zhang et al, 33 who observed a nonmonotonic change in the sliding angle with varying the number of brushes. The authors put forward a hypothesis about the relationship between film slippery properties and viscoelasticity.…”

“…Deposition from supercritical and subcritical CO 2 -based solutions expands the applicability of slippery polymer coatings to textiles, electrodes, and other substrates with complex morphology. We have recently demonstrated the possibility of using supercritical CO 2 for one-stage thin organogel SLIPS synthesis. , It has been shown that the pinning force of the test droplets in the transition from dry to swollen fluorinated polymer matrix is well described by the de Gennes theory of diluted defects …”