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Colorimetric sensor

a colorimetric sensor and multi-layer technology, applied in the field of colorimetric sensors, can solve the problems of many of these systems having lifetime limitation problems and not being useful for simple visual indication

Inactive Publication Date: 2004-04-01
3M INNOVATIVE PROPERTIES CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention is about colorimetric sensor films that can detect the presence and concentration of an analyte by measuring changes in optical thickness. The films are flexible and robust, and can provide fast and reversible responses. They can be designed to have a variety of chemistries that can detect different analytes. The films can be easily processed and have a unique design that allows for a reversible or permanent change in color upon exposure to the analyte. The films can be used for detecting the presence and concentration of various analytes in gaseous or liquid media. The detection is typically visible to the unaided human eye or can be detected using suitable detection mechanisms. The films can also be designed to lose perceptible color when delamination occurs.

Problems solved by technology

Moreover, many of these systems have lifetime limitation issues, due to photo-bleaching or undesirable side reactions.
Other optical sensing techniques, such as surface plasmon resonance and spectral interferometry, require substantial signal transduction hardware to provide response, and thus are not useful for simple visual indication.

Method used

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Examples

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example 1

[0074] A multi-layered calorimetric sensor film was produced via the deposition method described in U.S. Pat. No. 5,877,895.

[0075] An aluminum reflective layer (100 nm) and polymeric detection layer (500 nm) were sequentially deposited upon a polyester substrate layer (50 .mu.m) in a single pass (15.24 m / min) through a vacuum web system. The aluminum reflective layer was thermally evaporated by feeding 0.1587 cm diameter aluminum wire (Alcoa stock number 1199, Pittsburgh, Pa.) onto an electrically heated (7V, 1250 amp) evaporation bar at a feed rate of 225 mm / min. The polymeric detection layer (500 nm) was deposited followed by an electron beam cure of 6.9 W-Sec. The monomer composition was a 48.5 / 48.5 / 3 by weight mixture of lauryl acrylate (available from Sartomer, Exton, Pa.) / IRR214 (a proprietary hydrocarbon diacrylate, available from UCB Chemicals, Drogenbos, Belgium) / Ebecryl170 (a phosphoric acid monoacrylate compound also available from UCB Chemicals). Chromium (Academy Precis...

example 2

[0077] Visible reflectance spectra were taken of the multi-layered films before and after exposure to a range of solvent vapors. Film sections (2.54 cm square, from Example 1) were affixed on glass slides and exposed to saturated organic vapors within sealed jars. Once equilibrated, the exposed films were removed and covered immediately with glass cover slides to prevent vapor desorption. Reflectance spectra of the exposed materials were then taken using a diffuse reflectance UV-VIS spectrometer. For all organic vapors tested, substantial red-shifting of the reflectance maxima were observed upon analyte exposure. The reflectance maximum centered at 524 nm (before exposure), for instance, exhibits shifts to higher wavelengths (red shifts). The magnitudes of the shifts ranged from 22 nm (acetonitrile) to 116 nm (methylene chloride), as shown in Table 2. This example shows that the multi-layered calorimetric sensor films respond to organic vapors, exhibiting calorimetric shifts for hal...

example 3

[0078] In an effort to gauge the response sensitivity to different analyte vapors, sensor film, made as described in Example 1, was exposed to analytes at a range of concentrations using a simple flow-through setup. Concentrations (as determined by partial pressures) were controlled by bath temperatures. Air was bubbled through neat liquid analytes, which were chilled using cold temperature baths to control the vapor pressure. Mixtures of solid carbon dioxide (dry ice) and 3-heptanone or ethylene glycol gave bath temperatures of -38.degree. C. and -15.degree. C. respectively. An ice water bath was used to give temperatures of 0.degree. C. Vapor pressures for each analyte were calculated at these temperatures using data from the Handbook of Vapor Pressure (Yaws, C. L. Gulf Publishing: Houston, 1994). Each air / vapor stream was then flowed via a stainless steel cannula into a septum-sealed vial containing the multi-layered film. The color changes of each film on exposure were monitored...

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Abstract

Disclosed herein are calorimetric sensor films comprising a reflective layer, polymeric detection layer, and semi-reflective layer. Also disclosed are devices comprising the colorimetric sensor films and methods of making the films and devices.

Description

[0001] This disclosure relates to colorimetric sensor films.[0002] The development of robust chemical sensors for a range of analytes remains an important endeavor for applications such as environmental monitoring, product quality control, and chemical dosimetry. Among the many methods available for chemical sensing, calorimetric techniques remain advantageous in that the human eye can be used for signal transduction, rather than extensive instrumentation.[0003] Though calorimetric sensors currently exist for a range of analytes, most are based upon employing dyes or colored chemical indicators for detection. Such compounds are typically selective, meaning arrays are necessary to enable detection of various classes of compounds. Moreover, many of these systems have lifetime limitation issues, due to photo-bleaching or undesirable side reactions. Other optical sensing techniques, such as surface plasmon resonance and spectral interferometry, require substantial signal transduction ha...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): G01N21/78G01N31/22G01N33/52
CPCG01N21/78G01N33/525G01N31/22
Inventor RAKOW, NEAL ANTHONYLYONS, CHRISTOPHER STEWARTMAKI, STEPHEN PAUL
Owner 3M INNOVATIVE PROPERTIES CO
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