Abstract:SummarySorbent and functionalized polymers play a key role in a diverse set of fields, including chemical sensors, separation membranes, solid-phase extraction techniques, and chromatography. Sorbent polymers are critical to a number of sensor array or "electronic nose" systems. The responses of the sensors in the array give rise to patterns that can be used to distinguish one compound from another, provided that a sufficiently diverse set of sensing materials is present in the array. Figure S1 illustrates the… Show more
“…Bisphenol-containing polymers (referred to as BSP polymers) were prepared by this technique. This synthesis technique can potentially be used to prepare a great variety of sorbent polymers with tunable chemical and physical properties, with the option of cross-linking the materials via olefinic end groups. , The bond-forming reaction for these polymerizations is the hydrosilylation reaction, whose use in generating polymers of many architectures and functionalities has been reviewed …”
Section: Sensing Materialsmentioning
confidence: 99%
“…This synthesis technique can potentially be used to prepare a great variety of sorbent polymers with tunable chemical and physical properties, with the option of crosslinking the materials via olefinic end groups. 155,158 The bond-forming reaction for these polymerizations is the hydrosilylation reaction, whose use in generating polymers of many architectures and functionalities has been reviewed. 158 Recently Rapp and co-workers described an approach for cross-linking a great variety of substituted siloxane polymers for use on SAW sensors in an array.…”
Section: Sensing Materialsmentioning
confidence: 99%
“…155,158 The bond-forming reaction for these polymerizations is the hydrosilylation reaction, whose use in generating polymers of many architectures and functionalities has been reviewed. 158 Recently Rapp and co-workers described an approach for cross-linking a great variety of substituted siloxane polymers for use on SAW sensors in an array. 14 Free radical reactions to cross-link the polymers were initated with ultraviolet light and 2,2diethoxyacetophenone as the photoinitiator.…”
“…Bisphenol-containing polymers (referred to as BSP polymers) were prepared by this technique. This synthesis technique can potentially be used to prepare a great variety of sorbent polymers with tunable chemical and physical properties, with the option of cross-linking the materials via olefinic end groups. , The bond-forming reaction for these polymerizations is the hydrosilylation reaction, whose use in generating polymers of many architectures and functionalities has been reviewed …”
Section: Sensing Materialsmentioning
confidence: 99%
“…This synthesis technique can potentially be used to prepare a great variety of sorbent polymers with tunable chemical and physical properties, with the option of crosslinking the materials via olefinic end groups. 155,158 The bond-forming reaction for these polymerizations is the hydrosilylation reaction, whose use in generating polymers of many architectures and functionalities has been reviewed. 158 Recently Rapp and co-workers described an approach for cross-linking a great variety of substituted siloxane polymers for use on SAW sensors in an array.…”
Section: Sensing Materialsmentioning
confidence: 99%
“…155,158 The bond-forming reaction for these polymerizations is the hydrosilylation reaction, whose use in generating polymers of many architectures and functionalities has been reviewed. 158 Recently Rapp and co-workers described an approach for cross-linking a great variety of substituted siloxane polymers for use on SAW sensors in an array. 14 Free radical reactions to cross-link the polymers were initated with ultraviolet light and 2,2diethoxyacetophenone as the photoinitiator.…”
“…11 A common approach to offset this effect has been to introduce silicon-carbon or silicon-oxygen bonds into the polymer backbone, which effectively lowers the T g . 5,14,16c,17-18, 21,22 With the notable exception of two systems where dendritic polymers were used, 25,26 all hydrogen-bond acidic polymers developed to date for vapor-sensing applications have had linear architectures. However, the former may be expected to possess certain advantages over the latter, including higher molecular density of exo-presented functional groups for improved sensitivity and lower density of segmental entanglements for faster diffusion of vapor molecules in and out of the polymer matrix.…”
Section: Introductionmentioning
confidence: 99%
“…Conveniently, many polymers exhibiting these types of solubility interactions are commercially available with the notable exception of hydrogen-bond acidic polymers, which are of critical importance for the detection of hydrogen-bond basic entities such as nerve agents (Figure ) − ,16a,16b and explosives. −,16c,− They also provide greater chemical diversity and result in better performance of the sensor array as a whole . A particularly effective means of enhancing hydrogen-bond acidity of a polymer has been to incorporate phenol or fluorinated alcohol groups. ,,,,− These groups have high polarity, but they generally increase the polymer glass-transition temperature ( T g ) and lower the rate of vapor diffusion if the T g is near or above room temperature . A common approach to offset this effect has been to introduce silicon−carbon or silicon−oxygen bonds into the polymer backbone, which effectively lowers the T g . ,,16c,−,, 1 Selected nerve agents and nerve agent simulant DMMP.…”
A series of novel hyperbranched hydrogen-bond acidic polymers for surface acoustic wave (SAW) sensor applications were prepared by functionalizing hyperbranched polycarbosiloxanes or polycarbosilanes with phenol or hexafluoro-2-propanol groups. Starting polymer, sensor polymer, and reagent structures were confirmed by IR, 1 H, 13 C, and 29 Si NMR, SEC, or GCMS as appropriate. The hyperbranched sensor polymers were coated onto 500 MHz SAW platforms and their responses to the nerve agent simulant dimethyl methylphosphonate (DMMP) were studied. The hyperbranched sensor polymers with phenol groups gave very high initial responses to DMMP which dropped to 30% of the initial levels over a period of 6 months, and the hyperbranched sensor polymers with hexafluoro-2-propanol groups gave lower initial responses that did not change with time. Hence, the long-term performances of hyperbranched phenolic sensor polymers and hyperbranched hexafluoro-2-propanol sensor polymers were found to be comparable.
The solvatochromic dye Nile Red dispersed in selected hydrogen bond acidic polymer matrixes demonstrated strong fluorescence enhancement at the presence of dimethyl methylphosphonate (DMMP) vapors. Two hydrogen bond acidic polymers were examined as dye matrixes, one with fluorinated alcohol groups on a polystyrene backbone (PSFA) and the other with fluorinated bisphenol groups alternating with oligo(dimethylsiloxane) segments (BSP3). The combination of hydrogen bond acidic polymer (a strong sorbent for DMMP) with the solvatochromic dye led to initial depression of the dye fluorescence and a significant red shift in the absorbance and fluorescence spectra. DMMP sorption changed the dye environment and dramatically altered the fluorescence spectrum and intensity, resulting in a strong fluorescence enhancement. It is proposed that this fluorescence enhancement is due to the competition set up between the dye and the sorbed vapor for polymeric hydrogen-bonding sites. The highest responses were obtained with BSP3. DMMP detection has been demonstrated at sub-ppm DMMP concentrations, indicating very low detection limits compared to previous Nile Red/polymer matrix fluorescence vapor sensors. Nile Red/poly(methyl methacrylate) films prepared for comparisons exhibited substantially lower response to DMMP. Rational selection of polymers providing high sorption for DMMP and competition for hydrogen-bonding interactions with Nile Red yielded flourescent films with high sensitivity.
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