Application of supramolecular chemistry in the development of ion-selective CHEMFETs

✍ Scribed by David N. Reinhoudt

• Book ID: 103960339
• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 619 KB
• Volume: 6
• Category: Article
• ISSN: 0925-4005
• DOI: 10.1016/0925-4005(92)80052-y

✦ Synopsis

The construction of chemical sensors requires the integration of a sensing molecule and a transducing element. We have developed an integrated CHEMFET on the basis of an SO, ISFET by covalently linking a hydrophilic polyHEMA layer to the SO, gate oxide and a hydrophobic sensing membrane that contains the sensing molecule to this polyHEMA layer. The optimized material for the sensing membrane is a terpolymer of different siloxanes. The sensing molecules that we have studied were designed for a high K+, Na+, Ca*+ and Ag+ selectivity. Typical examples of such molecules are hemispherands or calix[4]arene crown ethers for K+ and tetra-0-alkylated calix[4]arenes in the cone conformation for Na+ or Ag+. The sensing molecules can be present as mobile hydrophobic species or they can be covalentjy attached to the sensing membrane. We have compared both possibilities and in both cases a durable sensor can,be obtained. The sensors that have covalently attached receptors' exhibit fast response times and are chemically: stable for prolonged periods ( 3200 days).

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