Effect of Nanoparticle Sizes and Number Densities on the Evaporation and Dryout Characteristics for Strongly Pinned Nanofluid Droplets

Abstract

A microfabricated linear heater array operating in a constant voltage mode has been used to study the effect of nanoparticle size on the evaporation and dryout characteristics of strongly pinned nanofluid droplets. Four different nanofluids have been tested, containing 2-nm Au, 30-nm CuO, 11-nm Al2O3, and 47-nm Al2O3 nanoparticles, each of 5-muL droplets with 0.5 vol % in water. Nanofluid droplets show strong pinning along the droplet perimeter and, upon evaporation, leave a ring-shaped nanoparticle stain. Particle size is seen to have a clear and strong effect on the dryout stain pattern, while heater temperature seems to have little effect. With the assumption of axi-symmetry, tomographic deconvolution of measured data from the linear heater array allows for examination of the spatially and temporally resolved temperature and heat flux characteristics of the evaporating nanofluid droplets.

Dip coating of charged colloidal suspensions onto substrates with patterned wettability: Coating regime maps

“…Segregation of particles implies lateral flow of particles occurring from the center to the edges of a hydrophilic stripe. The formation of non-uniform deposits of colloidal particles on substrates has been studied by several authors [35][36][37][38][39][40][41]. However, the effect of concentration of particles has not been discussed in these studies.…”

Effect of Surface Wettability on Crack Dynamics and Morphology of Colloidal Films

“…A distinct reduction in the number of microcracks apart from dependence on polarity, strength, and duration of applied field is observed for DC 25 and AC potentials. 26,27 The crack formation mechanism is a complex function of several parameters such as particle size, 28 charge, 29 shear modulus, 30 and process parameters such as evaporation rate. 31 The manipulation of substrate properties 32 to control the crack formation process has recently gained importance.…”

The effect of droplet ejection frequency on the dimensions of inkjet-etched micro-via holes in poly4(-vinyl phenol) thin films

“…However, it can be inferred that a low frequency was employed, which may explain these contrasting observations. Impacts of other parameters on the dimensions and appearances of the generated pattern in different polymer/solvent or particles/solvent systems have also been investigated [16][17][18][19][20][21][22][23]. Nonetheless, few studies focus on the interrelationship between droplet ejection frequency, the number of drops and the resulting via hole dimensions, which is significant in studying this inkjet-etching via hole formation technique and its feasibility for micro-via production in printed electronics applications.…”