Electrodes for Temperature Sensing or Heating

Fluids can be heated using an integrated resistive heating element  made from platinum. Locally high temperatures of several hundred degrees Celsius can be created within a couple of seconds using safe to use low voltages. For a homogeneous temperature across a large area of the chip the use of a transparent layer of electrically conductive ITO is usually advisable.

The integrated resistors can also be used to measure temperature, but it should be noted that there is some variation in the room temperature resistance from chip to chip and the temperature coefficient is not necessarily the same as for industrial Pt100 sensors. Sensors should therefore be individually calibrated.

The combination of electrical heaters and temperature sensors on a chip provides a convenient means to warm fluids inside microchannels to the desired temperature.