Oriented Boron Nitride in Calcium Alginate Matrix: A Sustainable Pathway to High-Efficiency Thermal Interface Materials.

With the rapid advancement of electronic devices toward higher frequencies, faster speeds, increased integration, and miniaturization, the resulting elevated operating temperatures pose significant challenges to the performance and longevity of electronic components. These developments have intensified the demand for high-performance thermal interface materials (TIMs). Conventional silicone rubber-based TIMs often suffer from silicone oil-bleeding and the volatilization of low-molecular-weight siloxanes under elevated temperatures and mechanical stress. The release of these volatile organic compounds can lead to their deposition on circuit boards and electronic components, causing signal interference or distortion in optical and electronic systems, ultimately compromising device functionality. Additionally, the intrinsic thermal conductivity of traditional TIMs is insufficient to meet the escalating demands for efficient heat dissipation. To overcome these limitations, this study introduces a novel, non-silicone TIM based on a calcium ion-crosslinked sodium alginate matrix, prepared via ion-exchange curing. This bio-derived polymer matrix serves as an environmentally benign alternative to silicone rubber. Furthermore, a brush-coating technique is employed to induce the oriented alignment of boron nitride (BN) fillers within the alginate matrix. Experimental characterization reveals that this aligned microstructure markedly enhances the thermal conductivity of the composite, achieving a value of 7.87 W·m-1·K-1. The resulting material also exhibits outstanding thermal and mechanical stability, with no observable leakage or condensate formation under high-temperature and high-pressure conditions. This work offers a new design paradigm for environmentally friendly, high-performance TIMs with considerable potential for advanced electronic and optoelectronic applications.