A lithium-containing, transparent glass-ceramic material is provided. Then, fluorine atoms exposed in the surface of the insulating film are removed therefrom by bombarding the surface of the insulating film with, for example, active species produced in a krypton gas plasma. Films suitable for use as a polyelectrolyte membrane are prepared from the sulfonated polymers. The bladder defines a bore configured to receive an expansion material, such that the expansion material applies an expansion force against the bladder, which thereby applies the expansion force against the implant body so as to cause the first linkage to expand greater than the second linkage.