Dynamics of macromolecules: A challenge for surface analysis

Abstract

XPS and contact angle measurement have been used to study oxygewplasma-treated polypropylene (PP) surfaces aged at variable temperatures. Surface rearrangement leading to low wettability has been observed, without alteration of the surface composition, as determined by XPS. Experimental results have been interpreted in terms of internal rearrangements of a modified layer, < 5 nm thick, formed on top of the PP and immiscible with it.We also modelled the composition of the surface layer and calculated the relative mobility of modified and non-modified polymer chains. On this basis, the experimentally observed behaviour can be interpreted in terms of surface rearrangement driven by a compromise between striving for lower surface tension and maximizing interand intramolecular interactions, mainly hydrogen bonds.The surface composition observed after treatment with plasma, corona, flame or other for enhancing surface tension is then time dependent. For this reason, the procedure used for surface analysis, namely the time allowed for surface equilibration, should be specified in reports.

Analysis for determining surface free energy uncertainty by the Owen–Wendt method

“…Substantial impact of shape and density of roughness on the examined surface has been found empirically [3,31]. (5) Surface (and the surface layer) physical and chemical homogeneity-physical andchemical heterogeneity (second source of thermodynamic hysteresis): The contact angle is influenced substantially by the migration of additional components (for plastics), the diverse supermolecular structure and surface heterogeneity due to functional groups of various sizes and characters emerging on it [32][33][34]. (6) Surface impurities.…”

Hydrophobic recovery of repeatedly plasma-treated silicone rubber. Part 2. A comparison of the hydrophobic recovery in air, water, or liquid nitrogen

“…However, because plasma-treated surfaces are frequently far from stable, the surface hydrophilicity created by the plasma treatment is often lost over time [2][3][4][5][6][7][8]. This so-called 'hydrophobic recovery' is caused, amongst others [2][3][4][8][9][10][11], by the *To whom correspondence should be addressed. mobility and reorientation of polymer chains in the treated surface layer.…”

Oxygen‐plasma‐treated polypropylene interfaces with air, water, and epoxy resins: Part I. Air and water

“…14 In part I1 of this work, we will discuss the properties of interfaces of untreated and oxygenplasma-treated polypropylene surfaces with epoxy resins. 15 …”