Evaporation of Water Droplets on Polymer Surfaces

Abstract

The evaporation of water droplets on polymer surfaces was investigated by using a digital image analysis technique. There were three distinct stages in the water evaporation process: a constant contact area mode, a constant contact angle mode, and a mixed mode that is independent of both the initial quantity of water droplets and the hydrophobic properties of the polymer surfaces. The physical factors influencing the first and second transitions in the evaporation process were found to be the attainment of the receding angle on the polymer surfaces and the Marangoni instability in the evaporating water droplets, which result from the concentration gradient of contaminants. This study also provides qualitative information about the microfluid flows inside the evaporating water droplets and the morphology of drying stains on polymer surfaces. The contaminants were found to be concentrated at the perimeter of the stains, in agreement with the observed outward microfluid flow in the mixed mode of the evaporation process.

Shapes and morphologies of inkjet‐printed nanosilver dots on glass substrates

“…In addition, constant contact area mode was observed during drying of single dots on both surfaces regardless of their diameters. [14] The first printed dots (N = 1) on each surface showed similar diameters under various substrate temperatures. While overprinting (N ≥ 2), since the second or third droplets are placed onto not glass surfaces but dots formed in advance, their spreading is influenced by the morphologies of the previously formed dots.…”

Evaporating drops on patterned surfaces: Transition from pinned to moving triple line

“…At this point in time, the evaporation process changes to the moving TL phase (see Fig. 3e-h) [17]. In both the phases II and III, the drop evaporation was observed to independently satisfy the D 2 law [18,19], according to which,…”

Electrocondensation and evaporation of attoliter water droplets: Direct visualization using atomic force microscopy

“…5(e) show that when the droplet volume is above 20 aL (see the 10 and 12 V curves in Fig. 5(e)), initial evaporation is fast (~5 min) and thereafter becomes gradual, much the same way as microliter droplets would behave [29]. Smaller droplets (< 20 aL, see the 8, 6, 5, 4, and 3 V curves in Fig.…”

“…The evaporation of macro-or micro-droplets of water is known to be a rapid process; the evaporation rate of a water droplet on a poly(methylmethacrylate) (PMMA) surface under similar humidity conditions is typically 0.1 µL/min [29]. Assuming that the observed trends in evaporation are independent of the droplet size, attoliter volumes of water such as those shown in Fig.…”