Summary: This review surveys methods for the fabrication, by plasma surface treatments or plasma polymerization, of polymeric surfaces and thin plasma polymer coatings that contain reactive chemical groups useful for the subsequent covalent immobilization, by solution chemical reactions or vapor phase grafting, of molecules or polymers that can exert bio‐specific interfacial responses. Surfaces containing amine, carboxy, hydroxy, and aldehyde groups are the subject of this review. Aminated surfaces have been fabricated using various plasma vapors or mixtures and have found wide use for bio‐interface applications. However, in many cases the amine surfaces have a rather limited shelf life, with post‐plasma oxidation reactions and surface adaptation leading to the disappearance of amine groups from the surface. Aging is a widespread phenomenon that often has not been recognized, particularly in some of the earlier studies on the use of plasma‐fabricated surfaces for bio‐interfacial applications, and can markedly alter the surface chemistry. Plasma‐fabricated surfaces that contain carboxy groups have also been well documented. Fewer reports exist on hydroxy and aldehyde surfaces prepared by plasma methods. Hydroxy surfaces can be prepared by water plasma treatment or the plasma polymerization of alkyl alcohol vapors. Water plasma treatment on many polymer substrates suffers from aging, with surface adaptation leading to the movement of surface modification effects into the polymer. Both hydroxy and aldehyde surfaces have been used for the covalent immobilization of biologically active molecules. Aging effects are less well documented than for amine surfaces. This review also surveys studies using such surfaces for cell colonization assays. Generally, these surface chemistries show good ability to support cell colonization, though the effectiveness seems to depend on the process vapor and the plasma conditions. Carboxylate co‐polymer surfaces have shown excellent ability to support the colonization of some human cell lines of clinical interest. Immobilization of proteins onto plasma‐carboxylated surfaces is also well established.XPS O/C ratios (00 emission) as a function of storage time, of plasma‐polymerized methyl methacrylate deposited at power levels of 5 and 40 W.magnified imageXPS O/C ratios (00 emission) as a function of storage time, of plasma‐polymerized methyl methacrylate deposited at power levels of 5 and 40 W.

Plasma polymers deposited from n-heptylamine onto silicon wafers have been found to form a porous microstructure when immersed in water and other solvents, with pores of dimensions and densities that vary considerably between coatings deposited under different plasma conditions. This solvent-induced pore formation was found to correlate with the observed percentage of extractable material. With low radio frequency (rf) power inputs, the resultant softer coatings possess considerably more extractable material than coatings deposited at higher applied power levels. The porosity is thus proposed to result from the formation of voids created by the extraction of soluble low-molecular-weight polymeric material, which produces shrinkage stress that the coating, firmly attached to the substrate, cannot relieve by macroscopic contraction. The microscopic contraction of plasma polymer volume creates voids that appear to span the entire film thickness. The effect of aging plasma polymers in air was also investigated. For films deposited at low power it led to reduced extraction of soluble material and different pore morphology, whereas for films deposited at higher rf power levels, the extracted amounts and pore formation were the same for aged coatings. It was also found that the density of surface amine groups was lower for films deposited under the two lowest power settings, in contrast to the commonly held belief that the use of minimal applied rf power aids retention of functional groups. These porous plasma polymer coatings with surface groups suitable for further interfacial chemical immobilization reactions may be useful for various membrane and biotechnology applications.

The preparation of thin film coatings with sulfonate and sulfate groups by plasma techniques is not straightforward due to limited volatility of suitable process vapours. We report a combination of plasma polymerisation and plasma treatment, treating heptylamine (HA‐SO2) and 1,7‐octadiene (OD‐SO2) plasma polymers with sulfur dioxide plasma. HA‐SO2 and OD‐SO2 plasma polymer surfaces exhibited different compositions with the latter showing almost twice the amount of sulfur, as well as polysulfonate. Ageing of HA‐SO2 plasma polymer surfaces in air or saline solution led to the disappearance of oligomers containing sulfonate and sulfate. Angle‐dependent XPS analysis of HA‐SO2 plasma polymers suggested that sulfur containing groups reptated into the plasma polymer upon storage after preparation.

New siloxane coupling agents have been prepared by the platinum-catalyzed addition of CH2=CHSi(OR)3 silanes (R = CH3 or CH2CH2OCH3) to four different siloxanes, poly[(methylhydrogen)siloxane-co-dimethylsiloxane], poly[(methylhydrogen)siloxane] (dp = 33), tetramethyldisiloxane, and tetramethylcyclotetrasiloxane. These new hydrophobic materials offer a distinct alternative to conventional silane coupling agents, prevalent in many industrial applications. The new preparations allow for control of molecular weight, the extent of coupling functionality, and the distribution of coupling groups on the siloxane backbone. The use of 2D NMR experiments, COSY, and HETCOR indicated two modes of addition to the Si-H groups had occurred, Markovnikov and anti-Markovnikov. GPC, FTIR, and and 13C NMR were used to thoroughly characterize all the reaction products.

Fimbrolide-coated lenses show promise as an antibacterial and anti-acanthamoebal coating on contact lenses and appear to be safe when worn on the eye in an animal model.