The effect of gold nanoparticles on the spreading of triple line

Abstract

The work reports a unique phenomenon of gold nanoparticles on the formation of gas bubbles. The welldefined gold nanofluids prevent the spreading of triple line during bubble formation, i.e. the triple line is pinned somewhere around the middle of the tube wall during the rapid bubble formation stage whereas it spreads to the outer edge of the tube for pure liquid. Compared with pure liquid, adding nanoparticles raises bubble frequency and reduces departure bubble volume. Different to other observations of bubble dynamics in nanofluids under evaporation or boiling conditions, which are caused by the surface modification due to particle sedimentation, this work reveals an inherent feature of enhanced pinning of triple lines for well-defined nanofluids, which bears extensive implications to a number of nanoparticle-associated interfacial phenomena.

Controlled Assembly of Nanorod TiO2 Crystals via a Sintering Process: Photoanode Properties in Dye-Sensitized Solar Cells

“…One step: substrate was coated and dried, using 500 rpm for 250 sec.) Surface wettability has an important role on thickness of nanofluid on substrate [9][10][11][12][13][14][15][16]. The thickness of nanofluid decreases, as affinity of liquid for substrate increases.…”

Modification of the Young–Laplace equation and prediction of bubble interface in the presence of nanoparticles

“…As a result, the effects of nanoparticles can be observed much easily. For instance, the pinning behavior of the triple line inside a gold nanofluid has been observed, for the first time, by using the bubble growth method (see Figure 2) [9]. The pinning behavior of the triple line affects subsequently the dynamics of triple line, and the bubble growth and departure process [12].…”

“…Recently, experimental investigations have been conducted to study the behavior of the triple line, bubble growth and bubble departure inside water, silver, gold and alumina nanofluids from stainless steel orifices. It has been observed that nanoparticles play a significant role on the behavior of triple line and consequently they have a great potential to modify the dynamics of bubble growth and departure process [9,[11][12]14]. A similar experiment has been conducted to study bubble growth inside de-ionized water from 0.5 mm, 0.12 mm and 0.054 mm diameter orifices made by Plexiglas.…”

“…The behavior of triple line such as the radius of triple line and contact angle depends on the force balance between liquid-gas and solid surface tensions at the triple line (see Figure 1). Nanoparticles have significant roles on liquid-gas [4][5][6], solid surface tensions [7] and the force balance at the triple line, affecting its equilibrium and dynamic behaviors [9][10].…”

“…The modification of the effective thermophysical properties influences the pressure drop and heat transfer coefficient in macro/microchannels [2]. The modification of liquid-gas and solid surface tensions would change the force balance at the triple line and consequently affect its dynamic behavior [7][8] including the radius of triple line [9] and the bubble contact angle [5,10], which has significant effects on the bubble growth and departure process [11][12][13][14][15][16], as well as the boiling heat transfer [6,[17][18][19][20][21][22][23][24].…”