Chemically grafted polymeric filters for chemical sensors: Hyperbranched poly(acrylic acid) films incorporating {Beta}-cyclodextrin receptors and amine-functionalized filter layers
- Texas A and M Univ., College Station, TX (United States). Dept. of Chemistry
The authors report a new molecular-filter approach for enhancing the selectivity of chemical sensors. Specifically, they describe electrochemical sensors prepared from Au electrodes coated with {beta}-cyclodextrin-functionalized, hyperbranched poly(acrylic acid)(PAA) films capped with a chemically grafted, ultrathin polyamine layer. The hyperbranched PAA film is a highly functionalized framework for covalently binding the {beta}-cyclodextrin molecular receptors. The thin, grafted polyamine overlayer acts as a pH-sensitive molecular filter that selectively passes suitably charged analytes. Poly(amidoamine) dendrimers or poly-D-lysine is used as 10--15-nm-thick filter layers. The results show that at low pH, when the polyamines are fully protonated, positively charged redox probe molecules, such as benzyl viologen (BV), do not permeate the filter layer. However, at high pH, when the filter layer is uncharged, BV penetrates the filter layer and is reduced at the electrode. The opposite pH dependence is observed for negatively charged redox molecules such as anthraquinone-2-sulfonate (AQS). Both BV and AQS specifically interact with the {beta}-cyclodextrin receptors underlying the polyamine filter layers.
- Research Organization:
- Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
- Sponsoring Organization:
- National Science Foundation, Washington, DC (United States); Sandia National Labs., Albuquerque, NM (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 680011
- Report Number(s):
- CONF-980314-; ISSN 0743-7463; TRN: IM9941%%52
- Journal Information:
- Langmuir, Vol. 15, Issue 3; Conference: American Chemical Society (ACS) meeting, Dallas, TX (United States), 26 Mar - 2 Apr 1998; Other Information: PBD: 2 Feb 1999
- Country of Publication:
- United States
- Language:
- English
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