In response to the limitations imposed on the microelectronics industry by electronic crosstalk losses and signal delays, as well as the rapid accumulation of heat, intrinsically low dielectric and high thermal conductivity materials are in urgent demand. Here, a self-curable biobased silane precursor (M@KH590) with a biphenyl unit was synthesized. A series of films (magnolol polysiloxane films (MPSOs)) were prepared using simple sol–gel film conversion and annealing and modulated intermolecular forces and molecular structure. The red-shift of the UV–vis absorption indicated that a larger π–π conjugated system was established. As a result, the through-plane thermal conductivity of MPSO-140 was 0.601 W·m^–1·K^–1, which was more than three times that of the pure polysiloxane material. Meanwhile, MPSO-140 exhibited excellent intrinsic low dielectric properties (D_k = 2.52, D_f = 0.000572, and f = 100 MHz). This was mainly attributed to the reduction of highly polar substances and groups as well as the difficulty in polarizing a π–π conjugated system. Based on rigid biphenyl units and high cross-link density, the tensile strength and modulus of MPSO-140 were 17.42 MPa and 2.61 GPa, respectively, showing prominent mechanical properties. In addition, MPSO-140 exhibited excellent water resistance (water contact angle and 72 h water absorption of 104.8° and 0.19%, respectively) and electrical insulation, showing great potential for practical applications. The study broadened the way toward overcoming the contradiction between low dielectric and high thermal conductivity by simultaneously introducing large free volume and modulating the intermolecular forces and molecular structure in a simple and effective way.

中文翻译：

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本征低介电率和高导热率生物基（木兰醇）聚硅氧烷薄膜的简单制备


为了应对电子串扰损耗和信号延迟以及热量的快速积累对微电子行业施加的限制，迫切需要本质上的低介电和高导热材料。在这里，合成了一种具有联苯单元的自固化生物基硅烷前驱体 （M@KH590）。使用简单的溶胶-凝胶膜转化和退火以及调制的分子间作用力和分子结构制备了一系列薄膜 （magnolol polysiloxane films （MPSOs））。UV-vis 吸收的红移表明建立了一个更大的 π-π 共轭系统。结果表明，MPSO-140 的平面热导率为 0.601 W·m^–1·^K-1 的 1 倍，是纯聚硅氧烷材料的三倍多。同时，MPSO-140 表现出优异的固有低介电性能 （D_k = 2.52， D_f = 0.000572， and f = 100 MHz）。这主要归因于高极性物质和基团的减少以及极化 π-π 共轭系统的困难。基于刚性联苯单元和高交联密度，MPSO-140 的拉伸强度和模量分别为 17.42 MPa 和 2.61 GPa，表现出突出的力学性能。此外，MPSO-140 表现出优异的耐水性（水接触角和 72 小时的吸水率分别为 104.8° 和 0.19%）和电绝缘性，显示出巨大的实际应用潜力。该研究通过同时引入大自由体积并以简单有效的方式调节分子间力和分子结构，为克服低介电和高热导率之间的矛盾拓宽了道路。