Hybrid Organic/Inorganic Copolymers with Strongly Hydrogen-Bond Acidic Properties for Acoustic Wave and Optical Sensors

Abstract

Hybrid organic/inorganic polymers have been prepared incorporating fluoroalkyl-substituted bisphenol groups linked using oligosiloxane spacers. These hydrogen-bond acidic materials have glass-to-rubber transition temperatures below room temperature and are excellent sorbents for basic vapors. The physical properties such as viscosity and refractive index can be tuned by varying the length of the oligosiloxane spacers and the molecular weight. In addition, the materials are easily cross-linked to yield solid elastomers. The potential use of these materials for chemical sensing has been demonstrated by applying them to surface acoustic wave devices as thin films and detecting the hydrogen-bond basic vapor dimethyl methylphosphonate with high sensitivity. It has also been demonstrated that one of these materials with suitable viscosity and refractive index can be used to clad silica optical fibers; the cladding was applied to freshly drawn fiber using a fiber drawing tower. These fibers have potential as evanescent wave optical fiber sensors.

Resolving fundamental limits of adhesive bonding in microfabrication.

“…BSP3 was prepared as given in ref. [14]. The structures of PECH and BSP3 are shown in Figure 3 In the studies, PECH and BSP3 were dissolved in a solvent and then spin-coated onto silicon wafers at 5000 rpm for 40 seconds to produce thin films less than 50 nm in thickness.…”

Novel Optical Device Materials - Molecular-Level Hybridization

“…[50][51][52][53][54] Especially, this is a unique approach to create an effective optical grating, which brings a HUGE ACOUSTIC RESPONSE by setting up a molecularscale optical grating effect. By building up the periodic structure of long alkyl-chains in the hybrid glassy hosts, we obtained a HUGE ACOUSTIC WAVE, which hasn't been found.…”

Polymers for Chemical Sensors Using Hydrosilylation Chemistry

“…28,29 This polymer was rationally designed to have strongly hydrogen-bond acidic properties that are desirable for sorbing basic vapors. A great many basic organic solvents exist that are used industrially that one might want to detect.…”

“…Accordingly, a number of synthetic materials have been prepared and investigated as sensor phases, most of which incorporate hexafluoroisopropanol moieties as the hydrogen-bond acidic group. [28][29][30][31][32][33][34][35][36][37][38][39] A study several years ago compared the hydrogen-bond acidities of several propyl-or allylsubstituted bisphenol structures using inverse gas chromatography and LSERs. 40 It was shown that fluorinated bisphenol-A structures were substantially more hydrogen-bond acidic than non-fluorinated analogs; fluorination improved sorption of basic compounds by factors of 100 or more.…”

“…28,29,41 Figure 5 shows the calibration curves for SAW sensors coated with BSP3, fluoropolyol (FPOL), and polydimethylsiloxane (PDMS) when tested against dimethyl methylphosphonate, a nerve-agent simulant. FPOL is a sensor coating for nerve agents described in the past, 26,27,33,42 and PDMS serves as an example of a sorbent polymer lacking functionalities designed for sorption of basic vapors.…”