Inducing arbitrary vapor pressures, and quantifying leakages

Abstract

We generalize the Maxwell drop evaporation equation to cover the range from closed system to open system through semiclosed system where the evaporation is restricted to an arbitrary degree which we show how to characterize. We first consider a suspended drop, and then a drop contacting a surface where the surface's vicinity restricts the evaporation paths. We show how to use these results to obtain arbitrary values of vapor pressure by simple manipulations of the numbers and sizes of droplets added to the system for a constant leak size, or, alternatively, control the leak size with a valve for given sizes of drops. We further show how to use this result to quantify a leakage in a system. Such a leakage is characterized using a single parameter (leakage length) which the described method calibrates. The calibrated leakage length can be used for systematic control of vapor concentrations within the chamber. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4548–4553, 2016

Influence of nitrogen plasma treatment on the wettability of polyetheretherketone and deposited chitosan layers

“…The equilibrium contact angle [21][22][23][24][25][26][27][28][29][30] was calculated for all tested surfaces and its value is between the advancing and receding contact angles, however, it is not their average. The water contact angles for the surfaces obtained in this way were 71.2 ± 2.8° and 69.9 ± 2.2°, respectively.…”

“…It is almost impossible to satisfy these requirements under laboratory conditions. Thus, Tadmor [21][22][23][24][25][26][27][28][29][30] proposed another equation for calculation of the equilibrium contact angle.…”

“…Some theoretical approaches used for energy determination should be mentioned here, for example, the acid-base approach proposed by van Oss et al, [31][32][33] Newmann equation of state, [34] Owens and Wendt approach, [35] hysteresis approach proposed by Chibowski [36][37][38] , and others. [39][40][41] In this paper, the value of apparent surface energy from the LWAB, [31][32][33] Owens and Wendt [35] as well as CAH [36][37][38] approaches will be compared and the Tadmor [21][22][23][24][25][26][27][28][29][30] equilibrium contact angle will be used for calculations when these approaches are applied.…”

“…In this paper, the contact angle for diiodomethane was 19.1 ± 2.4°. The equilibrium contact angle [21][22][23][24][25][26][27][28][29][30] was calculated for all tested surfaces and its value is between the advancing and receding contact angles, however, it is not their average. Assuming that the advancing contact angle is the highest of possible contact angles on the tested surface and the receding one is the lowest, the calculated equilibrium contact angle can be very close to the Young contact angle.…”

Evaporation of ethanol/water mixture droplets on micro-patterned PDMS surfaces

“…Drop evaporation has many applications in fields such as microfluidics, lab-on-a-chip, ink-jet printing, combustion and pesticide spraying [1][2][3][4][5][6][7]. In 1977, Picknett and Bexon [8] pioneeringly defined three evaporation modes, viz., constant contact radius mode (CCR mode), constant contact angle mode (CCA mode) and mixed mode.…”