Green thin polymer film metallization using supercritical carbon dioxide

Abstract

It is shown that low-density polymer layers created by supercritical carbon dioxide (scCO 2 ) processing can be exploited to enhance metallization of thin polymer films. Spun-cast thin films were exposed to scCO 2 within the narrow temperature and pressure regime known as the 'density fluctuation ridge', where excess swelling of the polymer thin films was induced, and the swollen structures could be subsequently preserved by quick evaporation of CO 2 . X-ray reflectivity (XR) measurements proved that the 'expanded' films had a broader interfacial width between the polymer and deposited metal layers, regardless of the polymer film thickness or choice of polymers. Furthermore, standard peel test showed a drastic enhancement in adhesion between the polymer and metal layers, which correlates with the XR result: the broader interfacial width indicates increased adhesion.

Fabrication of Responsive, Softening Neural Interfaces

“…The specific parameter of interest is the adhesion of the electrode to the substrate. Polymer substrates are often chemically modified after polymerization to introduce oxygen‐containing functional groups to increase adhesion 46, 47. When a polymer is polymerized directly onto a surface as in the described transfer process, the high mobility in the monomeric state allows for formation of the most favorable interaction, both mechanically and chemically, with the electrode.…”