Non-Contact and Self-Calibrated Photopyroelectric Method for Complete Thermal Characterization of Porous Materials

Area of Science:

• Condensed matter physics
• Materials science
• Thermal analysis

Background:

• Photopyroelectric (PPE) calorimetry is a powerful thermal analysis technique.
• Investigating porous materials using PPE has been historically challenging.
• Existing PPE configurations lack efficiency for complex material characterization.

Purpose of the Study:

• To develop a general theory for a novel photopyroelectric (PPE) configuration.
• To enable simultaneous measurement of thermal effusivity and diffusivity in solid samples.
• To extend PPE applications to the investigation of porous materials.

Main Methods:

• Development of a general theory for an opaque sample/transparent pyroelectric sensor PPE configuration.
• Utilizing combined back-front detection with frequency scan and phase self-normalization.
• Implementing a non-contact method with air as the coupling fluid at the sample/sensor interface.
• Employing a single-parameter fitting procedure for unique solution determination.

Main Results:

• The developed PPE configuration allows simultaneous measurement of thermal effusivity and diffusivity.
• A specific non-contact configuration is effective for complete thermal characterization of porous solids.
• The novel method simplifies the investigation of porous materials, previously difficult for PPE.
• Validation of the theory through applications on porous building materials and cellulose-based samples.

Conclusions:

• The proposed PPE method significantly expands the applicability of PPE calorimetry to porous materials.
• This technique offers a unique and efficient approach for thermal characterization of challenging porous solids.
• The study successfully bridges a gap in the application of PPE methods within condensed matter research.