Abstract: An apparatus and method for uniformly contacting an article with a treatment solution. Preferred embodiments are methods of uniformly tinting of contact lenses or uniformly surface modifying contact lenses. The method involves suspending the lens in the treatment solution by application of fluid flow, preferably sinusoidal or pulsed, in a direction opposite the stagnant force (i.e., sum of buoyancy and gravity forces) on the article. The fluid flow prevents the lens from contacting the container structure for periods sufficient to cause non-uniform treatment conditions, while continuously mixing the treatment solution to maintain uniform concentrations throughout.

Abstract: The invention relates to a process for modifying the surface characteristics of a preformed polymer substrate to impart altered properties thereto by graft polymerization on the substrate which includes: placing the polymer substrate in a plasma to form free radicals on the substrate; contacting the substrate having free radicals with oxygen to form hydroperoxy groups on the surface of the substrate; and graft polymerizing an ethylenically unsaturated monomer onto the surface of the polymer substrate.

Abstract: An apparatus and method for uniformly contacting an article with a treatment solution. Preferred embodiments are methods of uniformly tinting of contact lenses or uniformly surface modifying contact lenses. The method involves suspending the lens in the treatment solution by application of fluid flow, preferably sinusoidal or pulsed, in a direction opposite the stagnant force (i.e., sum of buoyancy and gravity forces) on the article. The fluid flow prevents the lens from contacting the container structure for periods sufficient to cause non-uniform treatment conditions, while continuously mixing the treatment solution to maintain uniform concentrations throughout.