The invention is directed to methods involving rewetting of expandable polymers
with a wettable liquid to allow for enhanced expansion at or below room temperature
without breakage, and in some cases, allows one to achieve a greater expansion
ratio than that allowed at elevated temperatures using known methods. The wettable
liquid can be formed of a drug and/or an agent, such that the resulting polymer
contains and emits the drug upon positioning at a target location of a patient
body. The expandable polymer can also have the drug or agent added to its structure
at a polymer resin preparation stage, through use of an aqueous solution mixed
with one or more fluoropolymers, or in a mixing stage. The present invention also
allows one to achieve material with unique properties and handling characteristics.
These properties included decreased material thickness, increased density, an altered
node/fibril morphology, and a more consistent web in the case of flat material.
This method is not limited to room temperature conditions and can be applied whenever
the expandable polymer material is wet with a wettable liquid, and the expansion
is performed at a temperature preferably below the vaporization or boiling points
of that liquid.
