Effect of nanoparticle size on sessile droplet contact angle

We report a significant variation in the static contact angle measured on indium oxide (IO) nanoparticle coated Si substrates that have different nanoparticle sizes. These IO nanoparticles, which have well defined shape and sizes, were synthesized by chemical vapor deposition in a horizontal alumina tube furnace. The size of the IO nanoparticles was varied by changing the source material, substrate temperature, and the deposition time. A sessile droplet method was used to determine the macroscopic contact angle on these IO nanoparticle covered Si substrate using two different liquids: de-ionized water and diethylene glycol (DEG). It was observed that contact angle depends strongly on the nanoparticle size. The contact angle was found to vary from 24° to 67° for de-ionized water droplet and from 15° to 60° for DEG droplet, for the nanoparticle sizes varying from 14 to 620 nm. The contact angle decreases with a decrease in the particles size. We have performed a theoretical analysis to determine the depende...

[1]  Marmur Line Tension and the Intrinsic Contact Angle in Solid-Liquid-Fluid Systems , 1997, Journal of colloid and interface science.

[2]  M. Podowski,et al.  Theoretical analysis on the effect of liquid droplet geometry on contact angle , 2005 .

[3]  J. S. Kim,et al.  2,11,18,21,24-Pentaoxatetra­cyclo­[23.4.0.04,9.012,17]­nonaicosa-1(25),4(9),5,7,12(17),13,15,26,28-nonaene , 2001 .

[4]  D. K. Owens,et al.  Estimation of the surface free energy of polymers , 1969 .

[5]  C. Hsieh,et al.  Influence of surface roughness on water- and oil-repellent surfaces coated with nanoparticles , 2005 .

[6]  P. Ajayan,et al.  Effect of nanoparticles on sessile droplet contact angle , 2006, Nanotechnology.

[7]  Kirsten Bobzin,et al.  The effect of PVD layer constitution on surface free energy , 1999 .

[8]  Dongqing Li Drop size dependence of contact angles and line tensions of solid-liquid systems , 1996 .

[9]  R. Friend,et al.  Surface energy and polarity of treated indium–tin–oxide anodes for polymer light-emitting diodes studied by contact-angle measurements , 1999 .

[10]  Y. Zhao,et al.  Water contact angles of vertically aligned Si nanorod arrays , 2004 .

[11]  E. Ruckenstein,et al.  Microscopic interpretation of the dependence of the contact angle on roughness. , 2005, Langmuir : the ACS journal of surfaces and colloids.

[12]  A. Amirfazli,et al.  Status of the three-phase line tension: a review. , 2004, Advances in colloid and interface science.

[13]  H. Daiguji,et al.  Dipole moments of water molecules confined in Na-LSX zeolites - : Molecular dynamics simulations including polarization of water , 2006 .

[14]  N. Koratkar,et al.  Impact dynamics and rebound of water droplets on superhydrophobic carbon nanotube arrays , 2007 .

[15]  D. Grützmacher,et al.  Impact of nanometer-scale roughness on contact-angle hysteresis and globulin adsorption , 2001 .