Executive Summary : | Storing of food, particularly meat and fish products for longer time is generally done at sub-ambient temperature in refrigerators or in cold storages. The detection of spoilage of such products under sub-ambient temperature is difficult due to absence of low-temperature point of care spoilage detection sensors. Among various sensing technologies, chemiresistive method is particularly advantageous over other methods due to their point of care applicability, ease of use, low costs and durability. When an analyte (biomarkers of spoilage, gas or VOC) interacts with chemisorbed surface oxygen layer of a chemiresistive material, the electrical resistance of the material changes. Based on this change in resistance, an analyte can be detected and quantified. However, due to need of energy during surface reactions, chemiresistive method mainly works at high temperatures. Up until now, the operating temperature of chemiresistors could be reduced only up to room temperature. Hence a wide range of sensing applications at temperatures below ambient, such as detection of food product spoilage at refrigerated conditions and so on were considered to be outside the scope of chemiresistors. Very recently the group of PI was successful in developing a ceramic-polymer nanocomposite material that exhibited chemiresistive sensing at temperature below ambient, including sub-zero temperature up to -78 C. A new plausible mechanism based on enhanced surface area due to semiconductor metal oxide (SMO) supported unfurled polymeric network and exciton like quasiparticle formation and breakage could explain such unprecedented ultra-low temperature gas sensing. This breakthrough discovery has opened up an entire research field of developing chemiresistors for below ambient temperature applications. In this project, efforts will be put to develop ceramic-polymer chemiresistive nanocomposites for sensing meat and fish product spoilage at refrigerated conditions. Furthermore, efforts will also be put to understand the mechanism of low-temperature chemiresistive sensing. The striking aspect of the project is that instead of preparing a single type of (p- or n-type) materials, a combination of p-type and n-type components will be put together while making any composites of conducting polymer and semiconductor materials in order to get multiple space charge regions (for creating favorable conditions to form exciton like quasiparticles) and the composites with polymer will be prepared by in-situ polymerization in order to get proper unfurling of the polymeric network. The overall outcome of the project would be to generate knowledge on the parameters those are affecting sub-ambient gas-sensing properties of ceramic-polymer nanocomposite materials. The scientific knowledge generated from this project would be helpful in developing sensors for low-temperature applications, such as food quality monitoring at refrigerated conditions, sensing gasses at cold regions and so on. |
Co-PI: | Dr. Amarnath Reddy Allu, CSIR-Central Glass And Ceramic Research Institute, Kolkata, west Bengal-700032, Dr. Subhajit Das, CSIR-Central Glass And Ceramic Research Institute, Kolkata, west Bengal-700032 |