Singularities in hydrophobic recovery of plasma treated polydimethylsiloxane surfaces under non-contaminant atmosphere

Plasma Hydrophilization of Superhydrophobic Surface and Its Aging Behavior: The Effect of Micro/nanostructured Surface

“…the reorientation of polar groups), and the FAS chains diffused to the uppermost layer (i.e. the chains diffusion) …”

“…However, it is well known that plasma‐induced hydrophilicity has a tendency to recover to its initial state, namely, the aging behavior . Reorientation of polar groups into the bulk and chain diffusion are two commonly acknowledged mechanisms for aging behavior . The storage conditions, such as temperature and relative humidity, have been proved to be key factors influencing the aging behavior .…”

Surface Treatment of Polydimethylsiloxane (PDMS) with Atmospheric Pressure Rotating Plasma Jet. Modeling and Optimization of the Surface Treatment Conditions

“…Hydrophobic recovery is probably the main limitation related to plasma treatment of PDMS, an amorphous polymer, caused by the reorientation and migration of the polymeric chains after treatment . Indeed the hydrophobic recovery is particularly fast in atmospheric pressure plasma treatments as the complete recovery of the initial surface energy values of the air plasma torch treated‐PDMS within 1 h after treatment has been reported …”

Influence of Plasma Chamber Set‐Up on the Surface Modification of Non‐Vulcanized and Pure SBR Rubber Treated at Radio‐Frequencies Air Plasma

“…Aside this relaxation processes arising from diffusion of low molecular weight chains, a second and simultaneous relaxation occurs that involves the reorientation of polar groups at the surface. Contrary to the aforementioned diffusion of short chains, the reorientation processes of surface polar groups occur within much shorter time scales, contributing to the hydrophobic recovery during τ << 3 h. Finally, the contribution of organic contamination during the hydrophobic recovery is the same as it is independent of the properties of the subsurface region.…”

“…This entails the migration of non‐modified low molecular weight species from the bulk to the subsurface region, the migration of oxidized low molecular weight species from the topmost layer inside the bulk, the migration of unmodified macromolecules to the surface, the reorientation of the bulk polar chemical groups especially near the surface and even the relaxation of the surface roughness. Most of the time, surface de‐activation (decrease of hydrophilicity) proceeds through the combined effects of the aforementioned temperature‐dependent relaxation processes (which are driven by the same mechanisms detailed in Section 3.3) and organic contamination coming from the surrounding atmosphere …”