A study of surface dynamics of polymers. II. Investigation by plasma surface implantation of fluorine–containing moieties

Abstract

SynopsisMacromolecules at the surface of a polymeric solid have considerable mobility, and the specific arrangement of functional groups of macromolecules at the surface is dictated by the environmental conditions in which the surface is placed. Consequently, the change of environmental conditions, such as immersion in water or placement in a biological surrounding, could cause a cosiderable degree of change in the surface characteristics of a polymer from those evaluated in the laboratory against ambient air. The mobile nature of a polymer surface can be investigated by surface-implanting fluorine-containing moieties, mainly -CF,, by the plasma implantation technique and following the disappearance and reappearance of fluorine atoms on the surface. The disappearance rates (based on the immersion time in water at room temperature) of ESCA Fls signals, the decay rates of (advancing) contact angle of water, and the recovery of these values on heat treatment of water-immersed samples were measured as a function of crystallinity of polymer samples (at three levels of crystallinity) for poly(ethy1ene terephthalate) and nylon 6.

The influence of molecular weight on the properties of polyacetal/hydroxyapatite nanocomposites. Part 2. In vitro assessment

“…Moreover, it has been reported that a greater crystallinity can lead to a higher energy surface and lower contact angles [25]. Elsewhere, Yasuda and co-workers [26] have shown that PA-6 specimens with a wide range of bulk crystalline fractions (Xc00.25 to 0.46) give similar contact angles. This would indicate that as the polymer surfaces were covered with a thin skin, it seems unlikely that bulk crystallinity influenced the contact angles or hysteresis.…”

The hydrophilization of polystyrene substrates by 172-nm vacuum ultraviolet light

“…The surface reconstruction, that is, short-range segmental motion, probably took place in the topmost region located at less than the present XPS sampling depth of 3 nm, and led to the hiding of polar functional groups from the surface. In general, the surface reconstruction of polymer substrates treated by discharge methods proceeds so as to minimize the surface free energy and build up a homogeneous hydrocarbon-like surface [53,54]. On the other hand, the sample treated at 10 5 Pa (solid circles in Fig.…”

Reactions of polyethylene surfaces with the downstream products of an air plasma: Gas phase and surface spectroscopic studies

“…By using excited-state chemistry in corona discharge'-4 and glow-discharge plasma treatments:-8 a number of polymers have been modified before painting, printing, and lamination. Direct oxygen glow discharge treatment of polyethylene surfaces has been shown to lead to changes in surface energy, adhesion, and shear Plasma treatment of polymers has been extensively studied5.6, [12][13][14] to be able to control the chemical modification and the product surface characteristics. When placed in the plasma discharge, the sample is in a hot complex flow of energetic species (radicals, ions, electrons, and UV); it is impossible to study separately the reactions between the surface and each species under such conditions.…”