Penn State Chemical Engineering Faculty, Seong H. Kim Research

Faculty

Nanomaterials Research

Hydrophobic and Superhydrophobic Coating via Atmospheric RF plasma Processes

Superhydrophobic surface treatments of various substrates are of great interest in recent years. A surperhydrophobic surface is the one with water contact angle higher than 150° and very low contact angle hysteresis. On these surfaces, water droplets do not wet the surface at all and easily roll off removing dirt and debris. An example in the nature is the lotus leaf. In collaboration with Mr. Jeong-Hoon Kim (CJ Creations), we are developing a simple and manufacturable method for formation of superhydrophobic coatings on a wide range of substrates. The superhydrophobic coating is produced by an in-line atmospheric radio frequency (rf) glow-discharge plasma process. The process can be applied to flat surface such as metals, silicon wafers, and glasses as well as rough surfaces such as Kimwipe paper and cotton without any need of separate micro-roughening steps. The system does not require any vacuum lines and is operated in an in-line mode, not in a batch mode. So it can easily be scaled up for applications to large substrate surfaces or continuous processing. The process time for samples with a diameter of ~10 cm is only 1 ~ 2 minutes. The video clips linked below show water droplet bouncing off the suyperhydrophibically treated surfaces. We are currently looking for industrial collaboration on this atmospheric rf plasma applications. We are interested in industrial collaboration for commercialization of this atmospheric rf plasma technique.

Clean Si Wafer.

Superhydrophobic-treated wafer.

Untreated Cotton.

Superhydrophobic - treated cotton.

References:

S. H. Kim, J.-H. Kim, B. K. Kang, and H. S. Uhm, "Superhydrophobic CFx Coating with Atmospheric RF Plasma" Langmuir 2005, 21, 12213.

J.-H. Kim, G. Liu, and S. H. Kim, "Deposition of stable hydrophobic coatings with in-line CH4 atmospheric rf plasma" J. Mater. Chem. 2006, 16, 977.

S. M. Hong, S. H. Kim, J. H. Kim, and H. I. Hwang, "Hydrophilic Surface Modification of PDMS Using Atmospheric RF Plasma" Proc. International MEMS Conf. 2006, Program #213.