What Causes Poor Thermal Conductivity in Nanomaterials?
Several factors contribute to the poor thermal conductivity observed in nanomaterials:
Phonon Scattering: In nanomaterials, the presence of numerous interfaces, defects, and grain boundaries leads to increased phonon scattering. This scattering disrupts the heat flow, resulting in lower thermal conductivity. Quantum Confinement: At the nanoscale, electrons and phonons are confined in restricted dimensions, altering their behavior. Quantum confinement can reduce the mean free path of phonons, thereby affecting the material's ability to conduct heat. Surface-to-Volume Ratio: Nanomaterials have a high surface-to-volume ratio, which increases surface scattering of phonons. This scattering further impedes thermal conductivity. Material Interfaces: The interfaces between different materials or different regions within a single nanomaterial can create thermal resistance. This resistance, known as thermal boundary resistance or Kapitza resistance, can hinder effective heat transfer.
