Nanosecond Imaging of Microboiling Behavior on Pulsed-Heated Au Films Modified With Hydrophilic and Hydrophobic Self-Assembled Monolayers

Published

November 8, 2005

Author(s)

K M. Balss, Charles T. Avedisian, Richard E. Cavicchi, Michael J. Tarlov

Abstract

Fast transient microboiling has been characterized on modified gold microheaters using a novel laser strobe microscopy technique. Microheater surfaces of different hydrophobicity were prepared using self-assembled monolayers of hexadecane thiol (hydrophobic), and 16-mercaptohexadecanol (hydrophilic), as well as the naturally hydrophilic bare gold surface. The microheater was immersed in a pool of water and a 5 ms voltage pulse to the heater was applied, causing superheating of the water and nucleation of a bubble on the heater surface. Light from a pulsed Nd:Yag laser was configured to illuminate and image the sample through a microscope asssembly. The timing of the short duration (7.5 ns ) laser flash was varied with respect to the voltage pulse applied to the heater to create a series of images illuminated by the flash of the laser. These images were correlated with the transient resistance change of the heater both during and after the voltage pulse. It was found that hydrophobic surfaces produced a bubble that nucleated at an earlier time, grew more slowly to a smaller maximum size and collapsed more rapidly than bubbles formed on hydrophilic surfaces.

Citation

Langmuir

Volume

21

Issue

No. 23

Pub Type

Journals

Download Paper

https://doi.org/10.1021/La040137t

Keywords

bubble, laser strobe microscopy, microboiling, microbubble, nucleation, SAM, self-assembled monolayer

Citation

Balss, K. , Avedisian, C. , Cavicchi, R. and Tarlov, M. (2005), Nanosecond Imaging of Microboiling Behavior on Pulsed-Heated Au Films Modified With Hydrophilic and Hydrophobic Self-Assembled Monolayers, Langmuir, [online], https://doi.org/10.1021/La040137t (Accessed December 13, 2024)