Summary: Low‐pressure plasma polymerization coating, as described in this paper, is an ultimately green process that uses a minimum amount of substances and produces a minimum amount of effluent and hence does not require an environmental remediation process. The super‐green aspect of the processing entirely changes the equation for the viability of the process in industrial applications. The main hampering factors for the low‐pressure processes are 1) psychological fear of vacuum processes, 2) relatively high initial equipment costs, and 3) a lack of adequate cost estimate for the entire process. In many cases, the first two factors are enough for planners to shy away from this promising technology. However, when one examines the overall cost of processing as a whole, the cost of initial equipment often is not the decisive factor. Such cases are presented in the nano‐film coating applied in corrosion protection of aluminum alloys, steel, and surface‐state modification of contact lenses. The benefits of environmental friendliness, non‐hazardous processing and superior performance of products that can be achieved only by low‐pressure plasma polymerization coatings are more than enough to compensate the initial cost of the equipment.For nanofilm (20 nm) coatings, the most expensive annual operation cost is for wastewater treatment, which is much more than the initial cost of vacuum plasma polymerization reactor.magnified imageFor nanofilm (20 nm) coatings, the most expensive annual operation cost is for wastewater treatment, which is much more than the initial cost of vacuum plasma polymerization reactor.

The influence of ultra-thin (i.e., 5-50 nm) plasma polymer coatings on siloxane-based hydrogel contact lenses was investigated by electrochemical impedance spectroscopy (EIS). Impedance measurements as a function of frequency (Bode plots) were taken at regular intervals until steady impedance was obtained, indicating that the lenses were saturated. Appropriate equivalent circuit models were constructed to describe the salt intrusion characteristics of the plasma polymer-coated contact lenses. This provided information pertaining to the resistance and capacitance of interfacial and bulk layers in the plasma polymer-coated lenses. Resistance relates to ion permeability and capacitance for water uptake. This investigation showed that some of an ultra-thin layer of plasma polymer applied onto a dry hydrogel remains a contiguous film after the substrate hydrogel swells upon hydration. In some cases, however, the overall impedance of the coated lens is so low that the state of the plasma polymer layer after the hydration of the substrate hydrogel could not be judged by EIS.

Tubular blood-contacting polymeric materials were modified by plasma polymerization and evaluated in the baboon with respect to their capacity to induce both acute and chronic arterial thrombosis. Polymer surface composition was determined by electron spectroscopy for chemical analysis. Steady-state arterial thromboembolism was initiated by introducing tubular segments into chronic arteriovenous shunts. Rates of platelet destruction induced by the test materials were calculated from 111In-platelet survival measurements. Nine plasma polymers based on tetrafluoroethylene, hexafluoroethane, hexafluoroethane/H2, and methane, when deposited on silicone rubber, consumed platelets at rates ranging from 1.1-5.6 x 10(8) platelets/cm2-day. Since these values were near the lower detection limit for this test system, the plasma polymers were considered relatively nonthrombogenic. Acute thrombus formation was initiated by inserting expanded Teflon (Gore-Tex PTFE) vascular grafts into the shunt system. 111In-platelet deposition was measured by scintillation camera imaging over a 1-h exposure period. Standard PTFE grafts (10 cm x 4 mm i.d.) accumulated approximately 1 x 10(10) platelets over this interval. While modification of PTFE grafts with a plasma polymer based on hexafluoroethane/H2 did not alter graft surface morphology, platelet deposition was reduced by 87% as compared to the controls (p less than 0.001). We conclude that both the surface chemistry and texture of prosthetic materials influence thrombogenesis. The method of plasma polymerization may be useful for assessing the importance of these variables independently and, perhaps, for minimizing certain adverse blood-material interactions.

Ind. Eng. Chem. Prod. Res. Dev. 1984, 23, 153-162 153 (Y = probability of chain propagation density) of species i Registry No. Carbon monoxide, 630-08-0; ruthenium, 1440-18-8. Literature Cited Batchelder. R. F.; Pennllne, H. W.; Schehl, R. R. Technlcal Publication DOE/ PETC/lR-83/6, US.Composite hollow fiber reverse osmosis membranes were prepared by depositing a thin layer (10-50 nm) of plasma polymers on hollow fibers wlth porous walls (made of polysulfone). The coating was canied out in a semicontinuous manner with six strands of substrate fibers. Operational parameters which influence reverse osmosis characteristics of composRe membranes were investigated.

The reproducibility of the plasma polymerization process was examined in a semlcontlnuous coating of hollow fibers, 6 fibers In lengths of approximately 12-15 m, by evaluating the performance of reverse osmosis membranes. The uniformity of the coating along the length of hollow fibers, as well as the reproducibility of the process, was found to be satisfactory when electrodes were conditioned In the actual conditions of plasma polymerization to be employed and plasma polymerization conditions were carefully controlled. The durability of the coated hollow fibers was then Investigated In the following test media: hot water, low pH, high pH, and 0.1 % NaOCI solutions. A threshold value of glow discharge parameter W/FM was found to be crucial In the performance of the reverse osmosis membrane and durability of the coated hollow fibers. Plasma polymerized composite membranes showed remarkable durability.