Simultaneous Thermal Analysis (STA) in a Silicon Microplate

Simultaneous thermal analysis (STA) is a well-established characterization method that quantitatively measures changes in sample weight and endothermic/exothermic properties. Currently, commercial STA instruments have reached their maximum potential in terms of their sensitivity and application scope. This work innovatively uses microelectromechanical system (MEMS) technology to develop a monolithic integrated resonant microplate chip, which realizes on-chip simultaneous measurement of thermogravimetric analysis (TGA) and differential thermal analysis (DTA): high-sensitivity mass detection of microgram samples (resolution: 0.32 ng) is achieved through frequency changes of the resonant microplate, temperature changes are accurately monitored (sensitivity: 2.1 mV/°C) in combination with the integrated polysilicon thermocouples, and a power response value of 2.3 V/W is measured, which significantly exceeds those of an available instrument. Verification experiments based on the phase transition of metal standards and the decomposition of calcium oxalate monohydrate (CaC₂O₄·H₂O) show that the chip significantly improves the efficiency of thermal analysis while maintaining high precision. Due to the trace sample detection characteristics (microgram level), it can be safely used in the analysis of explosive materials such as trinitrotoluene (TNT), effectively avoiding the risk of deflagration and pollution caused by large sample volumes in the traditional TGA instrument. The miniaturized structure supports real-time observation with an optical microscope, creating a new dimension of the STA process visualization. The breakthrough results of this work provide an innovative path for the integrated and miniaturized development of thermal analysis technology and have significant application value in the fields of material characterization and hazardous substance measurement.