| AVS 60th International Symposium and Exhibition | |
| Thin Film | Wednesday Sessions |
| Session TF+AS+BI+EM+SE+SS-WeA |
| Session: | Applications of Self-Assembled Monolayers and Nano-Structured Assemblies |
| Presenter: | C. Wang, University of Melbourne, Australia |
| Authors: | C. Wang, University of Melbourne, Australia A. Wu, University of Melbourne, Australia R. Lamb, University of Melbourne, Australia |
| Correspondent: | Click to Email |
High orders of interfacial roughness are known to scatter light; as a result, superhydrophobic surfaces, which are inherently rough, generally appear opaque. Therefore, an ideal range of roughness that can provide both superhydrophobicity and low light scattering in the visible light spectrum is a highly attractive challenge. The use of self-assembling nanoparticles is a popular choice to generate the required roughness for superhydrophobicity. While such systems offer ease of fabrication and processing, coating thickness is generally kept to a minimum to reduce light scattering, below the light scattering threshold, typically in the sub-micron scale. The degree of roughness in a sol-gel synthesized coating can be manipulated using differences in solvent polarity and vapor pressures. There is a clear trend in solvent-particle and particle-particle interaction under polar and non-polar solvents, resulting in a difference in nanoparticle cluster size[1], which contributes to light scattering. Changes in vapor pressure can also result in surface morphology formation during the drying process. We demonstrate that a simple change in solvent polarity on a sol-gel system can increase the optical transparency of a coating of thickness > 1 μm from 82-96% to 93-100% transparent in the visible spectrum. Meanwhile, the increased drying temperature from 100°C to 350°C can transform the coating’s hydrophobicity to superhydrophobicity.
1. Khan, S.A. and N.J. Zoeller, Journal of Rheology, 1993. (6): p. 1225-1235.