Alternative entangled polymer matrices

Despite the universal adoption of PVC, some investigations have centred on the prospect of alternative matrix materials. Except for poly(vinylisobutyl ether) (71), poly(methyl methyl acrylate) (72), poly(methyl acrylate) (39) and poly(vinyl chloride/alcohol) copolymer (73), practically no functional calcium ISEs were realized with poly(vinylidene chloride) (19), cellulose acetate, ethyl cellulose, collodion or pyroxylin (11). Photocured sensor membranes based on acrylates are considered in section 3.4.4. 

Poly(urethane) can be substituted for PVC in nitrate sensor membranes (67). Nonetheless, such materials are unlikely to usurp the well-proven poly(vinyl chloride) matrix. It is essential to employ a proven PVC, e.g. Breon III EP, Flowell 470 or Fluka S 704, otherwise non-functional or poor-quality ISEs may be produced even with a well-tried cocktail. However, Silopren (a silicone rubber) offers a distinct advantage in that lipophilic anions do not interfere with its valinomycin electrode, and it is considered to have universal applicability for body fluids (41). 

---