| abstract |
An improvement in self-driven miniature fluid dispensers is disclosed. The basic components of the dispensers are: an outer rigid semipermeable cellulose membrane that acts as a housing, an inner collapsible bag housed within the membrane that is adapted to contain the fluid, a water-imbibing composition interposed between the outer membrane and the inner bag, and a port that extends from the interior of the bag to the exterior of the dispenser through which the fluid may be charged to and discharged from the dispenser. The improvement lies in using a blend of cellulose acetate butyrate and polymethylmethacrylate to make the outer membrane, thereby forming a membrane of reduced water permeability. |