Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Reexamination Certificate
2001-07-02
2003-10-07
Moore, Margaret G. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From silicon reactant having at least one...
C528S029000, C528S043000, C528S042000, C428S447000, C422S069000, C422S070000, C422S089000, C436S104000, C436S106000
Reexamination Certificate
active
06630560
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to a new class of chemoselective polymer materials. In particular, the invention relates to linear and branched polysiloxane compounds for use in various analytical applications involving sorbent polymer materials, including: chromatoghraphy, chemical trapping, and chemical sensor applications. These polymeric materials are primarily designed to sorb hydrogen bond basic analytes such as organophosphonate esters (nerve agents and precursors), and nitroaromatics (explosives).
2. Description of the Related Art
The use of sorbent chemoselective polymers for chromatography, chemical trapping, and chemical sensor applications is well established for technologies such as gas liquid chromatography, solid phase microextraction (SPME), and surface acoustic wave (SAW) sensors respectively. In each application, the sorbent polymer is applied to a substrate as a thin film and analytes are sorbed to the polymer material. A typical configuration for a chemical sensor incorporates a thin layer of sorbent polymer deposited on a transducer that monitors changes in the physicochemical properties of the polymer film and translates these changes into an electrical signal that can be recorded. By careful design of the polymer, both sensitivity and selectivity of a chemical sensor can be enhanced with respect to specific classes or types of analytes. Typically, a chemoselective polymer is designed to contain functional groups or active sites that can interact preferentially with the target analyte through dipole—dipole, van der Waals, or hydrogen bonding forces. The interaction between a chemoselective polymer and the analyte can even be regarded as a “lock and key” type interaction if multiple active sites in the polymer are spatially controlled so that an analyte with multiple functional sites can simultaneously interact with the polymer active sites.
The ideal polymer film for extended chemical sensor applications should exhibit reversible binding of analyte, high selectivity and high sorptivity, long term stability; and, as a thin film, offer fast sorption and desorption properties. To achieve these characteristics a polymer must have physical properties that are amenable to rapid analyte sorption and desorption, suitable choice of functional groups, and a high density of functional groups to increase the sorptive properties for target analytes. Polymers with suitable analyte sorption characteristics can be obtained commercially for most analytes of interest with the exception of hydrogen bond acid polymers for sorption of hydrogen bond basic vapors. Of the few polymers that are commercially available (such as polyvinylalcohol, polyphenol, and fomblin zdol), either the physical properties are not ideal with glass transition temperatures above room temperature, the hydrogen bond acidity is relatively weak, or the density of functional groups is low.
Fluorinated polymers with hydroxyl groups as part of the polymer repeating unit and, in particular, polymers containing the hexafluoroisopropanol (HFIP) functional group are a well established class of hydrogen bond acid polymers. (See McGill, R. A.; Abraham, M. H.; Grate, J. W.
CHEMTECH
1994,24 (9), 27; Ballantine, D. S.; Rose, S. L.; Grate, J. W.; Wohltjen, H.
Anal. Chem.
1986, 58,3058; Snow, A. W.; Sprague, L. G.; Soulen, R. L.; Grate, J. W.; Wohltjen, H.
J. Appl. Pol. Sci.,
1991, 43, 1659; Houser, E. J.; McGill, R. A.; Mlsna, T. E.; Nguyen, V. K.; Chung, R.; Mowery, R. L.
Proc. SPIE, Detection and Remediation Technologies for Mines and Minelike Targets IV,
Orlando, Fla., 1999, 3710, 394-401; Houser, E. J.; McGill, R. A.; Nguyen, V. K.; Chung, R.; Weir, D. W.
Proc. SPIE, Detection and Remediation Technologies for Mines and Minelike Targets V,
Orlando, Fla., 2000, 4038; Houser, E. J.; Mlsna, T. E.; Nguyen, V. K.; Chung, R.; Mowery, R. L.; McGill, R. A.
Talanta,
2001, 54,469 ; Grate, J. W.; Patrash, S. J.; Kaganove, S. N.; Wise, B. M.
Anal. Chem.
1999, 71,1033; all of which are incorporated herein by reference). The polymer fluoropolyol (FPOL) has become a standard material for many polymer based chemical sensor applications requiring hydrogen bond-acid polymers. (See: Ballantine, D. S.; Rose, S. L.; Grate, J. W.; Wohltjen, H.
Anal. Chem.
1986, 58, 3058; Snow, A. W.; Sprague, L. G.; Soulen, R. L.; Grate, J. W.; Wohltjen, H.
J. Appl. Pol. Sci.,
1991, 43, 1659; all of which are incorporated herein by reference). Recently reported polymers such as BSP3, SXFA, and CS3P2 have yielded improvements in sensitivity and response time relative to FPOL. (See: Houser, E. J.; McGill, R. A.; Mlsna, T. E.; Nguyen, V. K.; Chung, R.; Mowery, R. L.
Proc. SPIE, Detection and Remediation Technologies for Mines and Minelike Targets IV,
Orlando, Fla., 1999,3710,394-401; Houser, E. J.; McGill, R. A.; Nguyen, V. K.; Chung, R.; Weir, D. W.
Proc. SPIE, Detection and Remediation Technologies for Mines and Minelike Targets V,
Orlando, Fla., 2000, 4038; all of which are incorporated herein by reference).
Determining and/or monitoring the presence of certain chemical species within a particular environment, e.g., pollutants, toxic substances and other predetermined compounds, is becoming of increasing importance with respect to such areas as defense, health, environmental protection, resource conservation, police and fire-fighting operations, and chemical manufacture. Devices for the molecular recognition of noxious species or other analytes typically include (1) a substrate and (2) a molecular recognition coating upon the substrate. These devices may be used, for example, as stand-alone chemical vapor sensing devices or as a detector for monitoring different gasses separated by gas chromatography. Molecular recognition devices are described in Grate et al.,
Sensors and Actuators
B, 3, 85-111 (1991); Grate et al.,
Analytical Chemistry,
Vol. 65, No. 14, Jul. 15, 1993; Grate et al.,
Analytical Chemistry,
Vol. 65, No. 21, Nov. 15, 1993; and
Handbook of Biosensor and Electronic Noses,
ed. Kress-Rogers, CRC Press, 1996; all of which are incorporated herein by reference.
Frequently, the substrate is a piezoelectric material or an optical waveguide, which can detect small changes in the mass or refractive index, respectively. One illustrative example of a device that relies upon selective sorption for molecular recognition is known as a surface acoustic wave (SAW) sensor. SAW devices function by generating mechanical surface waves on a thin slab of a piezoelectric material, such as quartz, that oscillates at a characteristic resonant frequency when placed in a feedback circuit with a radio frequency amplifier. The oscillator frequency is measurably altered by small changes in mass and/or elastic modulus at the surface of the SAW device.
SAW devices can be adapted to a variety of gas and liquid phase analytical problems by designing or selecting specific coatings for particular applications. The use of chemoselective polymers for chemical sensor application is well established as a way to increase the sensitivity and selectivity of a chemical sensor with respect to specific classes or types of analytes. Typically, a chemoselective polymer is designed to contain functional groups that can interact preferentially with the target analyte through dipole—dipole, van der Waals, or hydrogen bonding forces. For example, strong hydrogen bond donating characteristics are important for the detection of species that are hydrogen bond acceptors, such as toxic organophosphorus compounds. Increasing the hydrogen bond acidity and the density of hydrogen bond acidic binding sites in the coating of a sensor results in an increase in selectivity and sensitivity of the sensor for hydrogen bond basic analytes.
Chemoselective films or coatings used with chemical sensors have been described by McGill et al. in
Chemtech,
Vol. 24, No. 9, 27-37 (1994), incorporated herein by reference. The materials used as the chemically active, selectively absorbent layer of a molecular recognition device have
Houser Eric J.
McGill Robert Andrew
Mlsna Todd
Forman Rebecca L.
Karasek John J.
Moore Margaret G.
The United States of America as represented by the Secretary of
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