(37e) Boosting Thermal Conduction Via Filler-Free Technology in Polymer Based Materials with Good Optical Transparency

Application of thermally conductive materials is quite diverse and broad ranging from aerospace to automobile to electronic packaging. Since several decades the research in this area has been confined to traditional thermally conductive polymer composite which are reinforced with metallic/ceramic/carbon fillers. These systems generally use high loading of fillers (+50 wt.%) to achieve required thermal conduction. This study presents for the first time a non-conventional technology using organic molecules for the development of thermally conductive and optically transparent polymeric materials for thermal management applications without incorporating any traditional metallic/ceramic/carbon fillers. Here we explore and exhibit the potential of engineering intermolecular interactions to develop thermal conductive pathways within polymer chains without adding fillers, thus developing better heat dissipating material. Intermolecular interactions like hydrogen bonding are used as an effective medium to drive the phonon (heat packet) propagation in the polymer based material incorporated with lower thermally conductive organic molecules. Phonon transport was driven by the “thermal bridges” designed through intermolecular hydrogen bonding between PVA and DEG. This study further explores the impact of functional group and length of “thermal bridges” to optimize the overall thermal conduction. Interestingly, these materials were found to have inverse thermal conductivity-crystallinity relationship which is usually an opposite trend than the present belief. Overall it was found that size, molecular geometry, terminal functional group of the thermal bridging molecule in host polymer are very crucial factors in determining thermal conductance. Principles presented in this study can be used for the design of thermally conductive and optically transparent material for heat management applications.