title: Potentiometric properties of ion-selective electrode membranes based on segmented polyether urethane matrices.
abstract: Potentiometric responses of polyurethane (PU)-based membranes containing valinomycin and varying amounts of plasticizer (DOA) and/or lipophilic additive (KTpClPB) were examined as a function of soft segment [poly(tetramethylene ether glycol)] contents in aromatic diisocyanate-based PU matrices. Upon increasing the weight percentages (w(soft)) of soft segments, which in part behave like a built-in plasticizer, providing the matrices with rubbery structure (glass transition temperature below -58 °C), the amounts of DOA and/or KTpClPB necessary to result in near-Nerntian response (e.g., slope > 50 mV/decade) to potassium were substantially lowered. The apparent effect of adding plasticizer to PU-based membranes was comparable to that resulting from an increase of free carrier concentration in normal PVC-based membranes. Owing to the chemical interaction between mobile anionic sites and urethane chains, plasticizer-free PU membranes could be prepared with the PU matrices with high soft segment contents (w(soft) ≥ 60 wt %). PUs composed of 60 ≤ w(soft) < 80 wt % were recommended as the matrix for fabricating ISE membranes with no or low plasticizer content.
authors.affiliation: Department of Chemistry and Research Institute of Basic Science, Kwangwoon University, Seoul 139-701, Korea.
authors.forename: S Y
authors.initials: SY
authors.lastname: Yun
authors.forename: Y K
authors.initials: YK
authors.lastname: Hong
authors.forename: B K
authors.initials: BK
authors.lastname: Oh
authors.forename: G S
authors.initials: GS
authors.lastname: Cha
authors.forename: H
authors.initials: H
authors.lastname: Nam
authors.forename: S B
authors.initials: SB
authors.lastname: Lee
authors.forename: J I
authors.initials: JI
authors.lastname: Jin