Universal approach for the fabrication of Ca2+-, K+- and NO3--sensitive membrane ISFETs

P.D. van der Wal, A. van den Berg, N.F. de Rooij

Research output: Contribution to journalArticleAcademicpeer-review

48 Citations (Scopus)
91 Downloads (Pure)


A new method to functionalize silanol-terminated polysiloxanes is presented. The method can be used for the realization of tailor-made ion-selective membranes. A siloxane copolymer containing polar cyano groups combined with a condensation-type cross linking overcomes the earlier encountered problem of high membrane resistance. After modification of this material with methacrylate groups, a photocurable polysiloxane was obtained. Potassium- and calcium-selective ISFETs with excellent sensitivities and selectivities (log KK,i<-3.5, i=Na+, Mg2+, Ca2+-log KCa,i<-3.2, i=Na+, K+, Mg2+) could be made with this material using photolithography. Also quaternary ammonium ion-exchange groups could be coupled to the polymer using the same technique. Using this modified polysiloxane we have been able to realize nitrate-sensitive ISFETs with a slope of 57-58 mV/decade, and a selectivity versus Cl- of log KNO3, Cl=-2.

Original languageEnglish
Pages (from-to)200-207
Number of pages8
JournalSensors and Actuators B: Chemical
Issue number1-3
Publication statusPublished - Mar 1994
Externally publishedYes


Dive into the research topics of 'Universal approach for the fabrication of Ca2+-, K+- and NO3--sensitive membrane ISFETs'. Together they form a unique fingerprint.

Cite this