Development of an advanced nanocalorimetry system for rapid material characterizations
The development of a versatile system capable of providing rapid, portable, and inexpensive detection of explosives and energetic compounds is needed critically to offer an enhanced level of protection against current and future threats to homeland security, as well as to satisfy a wide range of applications in the fields of forensic analysis, emergency response, and industrial hazards analysis. The hand-held nanocalorimeter will serve as a first-of-its-kind screening tools for explosive and energetic compounds directly in the settings where they are needed with high efficiency, reduced cost, and simplicity with ease of use. Unlike current explosives detectors, this system is based on calorimetric techniques that are inherently capable of providing direct measurements of energy release potential and therefore do not depend on prior knowledge of familiar compounds. The microfabricated calorimetry instrument consists of (i) a thermal control module incorporating arrays of microfabricated heaters and temperature sensors, as well as any necessary electronic interconnections, and (ii) a sample encapsulation module incorporating etched enclosures designed to accommodate either solid or liquid samples. Initial work has led to successful fabrication of a chip capable of sampling nano-sized solid or liquid compounds. Control algorithms incorporating the DSC principle have also been written using LabVIEW. Device performance of the original and redesigned chips were tested by studying the thermal transitions associated with the boiling points of acetone and pentane. With the redesigned chip, the heat loss issue was reduced: the measured input heat was reduced from 32 times of the required energy to 5 times of the required energy. Future work will focus on modifying the chip design and control algorithm to improve accuracy and sensitivity, developing a trace analysis software to link it to a database of explosive information, and adapting different fabrication procedures for high temperature operation and large scale production.