Changes Color upon Contact with Chemical Analytes to Detect and Quantify the Presence of a Liquid in Commercial Liquid Products
This chromogenic sensor uses shape memory polymer gratings to detect the concentration of ethanol in gasoline and other commercial liquid products. One of the most common uses of ethanol is as a fuel additive to reduce air pollution, and over 97 percent of all U.S. gasoline contains ethanol. However, ethanol has lower energy content than gasoline and corrodes aluminum and rubber components of fuel systems. Therefore many vehicles, such as aircraft and older automobiles, require gasoline with very low or zero ethanol content, leading to the necessity for easy, inexpensive tests for ethanol concentration. Although available electronic ethanol sensors are highly accurate, their high cost limits their market adoption rate. Other available ethanol tests, while having low cost, also have low accuracy and can only detect ethanol concentrations of around five percent or greater.
Researchers at the University of Florida have developed a low-cost, reusable, nonelectric chromogenic sensor that rapidly analyzes the concentration of ethanol in gasoline, drugs, or other liquid products. Users simply expose the sensor to a few drops of gasoline while a smartphone platform analyzes the color changes of the sensor to determine the ethanol concentration.
Application
Inexpensive and user-friendly colorimetric sensors scalable for mass manufacture that detect ethanol concentrations in gasoline and other liquid products
Advantages
- Rapidly and accurately detects ethanol concentrations in products ranging from gasoline to drugs, offering a low cost alternative to expensive electronic sensors
- Replicates the grating structure of optical discs using shape memory polymers, reducing manufacturing costs and enabling mass production of chromogenic sensors
- Features very simple and convenient operation, functioning similarly to colorimetric pH papers that analyze ethanol rather than pH
- Incorporates a smartphone platform for quantitative colorimetric analysis, supporting user-friendly, at home application
Technology
These sensors detect trace concentrations of ethanol in liquid mixtures by giving off specific colors upon exposure to different concentrations. To fabricate a sensor, a commercial polyurethane monomer and photoinitiator mixture pours onto the grating structure of a common optical disc, such as a DVD. After rapid photopolymerization, the polymer detaches from the disc while maintaining the chromatic grating structure. A simple mechanical compression process then deforms the polymer grating structure into a temporary configuration. When contacted with a liquid containing ethanol, the deformed polymeric structure of the sensor, with no structural color, gradually recovers back to the memorized grating structure according to the liquid’s ethanol concentration, subsequently causing an easily-perceived color change. An accompanying smartphone platform analyzes the change in color to rapidly determine the precise concentration of ethanol in the examined liquid.
Brochure
