Adaptable thermal conductivity characterization of microporous membranes based on freestanding sensor-based 3ω technique

• Adaptable thermal conductivity characterization for porous membranes is proposed.
• We model the heat transport process in the sensor-membrane measurement structure.
• Effect of loading pressure for the present method is investigated.
• Applicable thickness limit of membrane samples for the present method is discussed.
• Thermal contact resistance at the sensor-membrane interface is addressed in detail.

Adaptable thermal conductivity measurements of microporous membranes based on freestanding sensor-based 3ω technique is proposed. The adaptability and flexibility of the freestanding sensor enable microporous membranes with various mechanical and thermal properties to be easily sandwiched between the freestanding sensor and a semi-infinite thermally conductive substrate, assembling into a five-layer substrate-membrane-sensor-membrane-substrate configuration. A theoretical model for the calculation of membrane's thermal conductivity is provided by comparing the temperature difference between the five-layer configuration and a three-layer substrate-sensor-substrate configuration. The well agreed experimental results with the theoretically calculated values indicate that the present strategy can be widely applied to the thermal properties characterization of microporous membranes in membrane distillation.