Abstract:
Micro/nano thermogravimetry (TG) employing MEMS has significant potential to improve
the minimum sample mass and mass resolution as compared to commercial TG instruments.
Although there have been a few previous reports on MEMS TG, none of them have critically
analysed the obtained TG curve in detail. In this work, we have designed and fabricated a
microelectromechanical thermogravimetric device (MMTG) with integrated microheaters
and temperature sensors. The mass sensitivity of the device was estimated to be 0.89 pg Hz−1
which outperforms the standard TG approaches. We tested the MMTG performance with
CuSO4·5H2O crystals. The final mass loss ratio corresponds to the theoretically expected
value, although the obtained TG curve deviated from the standard TG curve of CuSO4·5H2O
obtained from commercial TG instruments. We attributed the deviation to the inherent
temperature non-uniformity, non-isothermal conditions and temperature gradients of metallicwire
based microheaters. Finite element (FE) simulations were carried out in order to confirm
and gain insights into the non-uniform heating phenomena of microheater and sample. Based
on the simulation results, we propose designs that can be realized to make MEMS TG a
successful enterprise.