Testing the self-cleaning properties of a coordination polymer surface

Abstract

It is well established that self-cleaning can be related to the hydrophobic or hydrophilic nature of a surface. Using adsorption chromatography, molecular simulations and wetting dynamics measurements, the self-cleaning properties of a new, strongly water resistant and hydrophilic cystine-containing coordination polymer (CP) were tested. Adsorption isotherms of n-octane and methanol were determined in the range of 313-343 K. Next the isosteric enthalpy of adsorption and the change in adsorption entropy were calculated to explain higher adsorption of methanol than n-butane. Performed chromatographic tests, molecular dynamics simulations and wetting dynamics experiments additionally prove that the Zn(Cys) 2 CP is a promising material for the application in the preperation of self-cleaning surfaces or coatings.

What Is the Value of Water Contact Angle on Silicon?

“…Consequently, the line tension finite size effects are negligible when considering droplets consisting of 6000 water molecules. Similar to the cylindrical droplet, the bottom of the spherical droplet is defined as the part of the density profile near the surface with the density of at least 0.5 g/ cm 3 , and again from Figure 5, we infer it to be z = 17.6 A.…”

“…Figure S1 shows a water contour calculated for k d = 0.147. The bottom of the droplet is defined as a part of the density profile near the surface with the density of at least 0.5 g/cm 3 and from this figure we identify this at z = 17.6 Å. Next, the least-square method of fitting the contour to the circle was applied, taking the points that are at a distance at least 10 Å from the surface.…”

“…Similar to the cylindrical droplet, the bottom of the spherical droplet is defined as the part of the density profile near the surface with the density of at least 0.5 g/ cm 3 , and again from Figure 5, we infer it to be z = 17.6˚A. From this figure we estimate the value of the substrate-water interaction strength at which the first order wetting transition takes place k w = 0.2237 or ε SiO , w = 2.6081 kJ/mole.…”

“…Once the initial minimization of the positions of water molecules was accomplished, the spherically symmetric drop is readily formed allowing the calculation of the radially symmetric density profile. From the radially averaged two-dimensional density profile (r, z), we evaluated the density contours satisfying 0.5 ± 0.03 g/cm 3 . Figure 5 shows the water drop contour calculated for k d = 0.147 and for three different numbers of water molecules, N SPC/E = 2000, 4000, and 6000, respectively.…”

“…Generally, it was shown that the increase or a decrease in the WCA value after airborne hydrocarbons adsorption can be observed. Recently, we also proved that if the affinity of water to a substrate is high water nanodroplet can completely remove light hydrocarbons from a surface and robust self-cleaning properties of a surface are observed [3]. There are few major topics that should be considered during silicon surface wetting.…”