Details

Autor(en) / Beteiligte

• Moffat, J. Ross
• Sefiane, Khellil
• Shanahan, Martin E. R

Titel

Effect of TiO2 Nanoparticles on Contact Line Stick−Slip Behavior of Volatile Drops

Ist Teil von

• The journal of physical chemistry. B, 2009-07, Vol.113 (26), p.8860-8866

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2009

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We describe an experimental investigation of the concomitant evaporation and (de)wetting behavior of sessile drops of ethanol, either pure, or containing small amounts of titanium oxide nanoparticles. Pure ethanol behaved in a more or less “ideal” manner, with constantly decreasing contact radius, at essentially constant contact angle. However, distinct “stick−slip” pinning behavior of the triple line occurred when nanoparticles were added to the base liquid. Increased nanoparticle concentration enhanced the “stick−slip” behavior. The observed behavior is attributed to the effects of particle accumulation near the contact line, caused by the now-established advective flow during evaporation. “Slip” behavior can be explained by hysteretic energy barriers, somewhat akin to line tension. The “stick” behavior was not complete: some triple line drift occurred (“pseudo-pinning”). It is postulated that this may be due to small-scale pinning of the triple line by deposited particles, or to increased effective viscosity due to high, local nanoparticle concentrations.