在微电子技术向着日益小型化、高集成化和大功率化方向发展的背景下，元器件的热积累问题愈发显著。如果无法及时有效地散失积聚热量，器件温度将迅速上升，这对其运行速度、精度、可靠性和使用寿命产生严重影响。因此，有效的散热已成为保证器件稳定运行和延长使用寿命的关键，这迫切需要开发具有高导热性和高绝缘性的柔性复合材料作为热管理材料实现绝缘场合的快速散热。聚乙烯醇(PVA)凭借其易于加工、优良绝缘性能以及良好光学透明性已成为微电子和电力设备封装等热管理材料领域的常用聚合物材料。然而，PVA的本征热导率(k值)很低，难以满足需要高绝缘及光学透明领域的电子设备及电力装备的封装散热需求。

针对此问题，本研究一方面在PVA中掺杂无机离子晶体和有机分子晶体，诱导其在PVA溶液中结晶，通过调控在PVA中的离子及分子晶体的形态及空间分布实现调控PVA导热性能的目的。另一方面，选择和PVA具有链间氢键作用的配体聚合物构筑共混聚合物，通过利用取向过程中形成的长程有序模板效应以及链间氢键的自动调控作用，实现了从微尺度到介观尺度多尺度上分子链取向，为声子传输提供了快速通道，并有效抑制载流子传输，从而实现同步调控PVA的导热与电绝缘性能的目的。主要研究内容如下：

(1) 选取易溶于水的氯化钠(NaCl)和氯化钾(KCl)两种无机离子晶体，通过调控无机盐用量、温度、浓度与其它条件，观察在PVA中的不同离子的结晶及晶体生长过程，并调控晶体在PVA中的空间分布以构筑不同形态的声子传递通路。研究发现，蒸发温度通过影响溶液挥发速率而影响晶体生长动力学，理解离子结晶速率及溶剂挥发速率之间竞争机制利于控制无机离子晶体在PVA基体中的形态及空间分布，从而构筑不同声子路径实现对PVA导热性能的调控。随着无机离子晶体含量的增加，复合材料的k值显著提升。在较低温下离子易于形成均匀有序的导热路径，因此PVA的k值增长显著，例如，在30 ^oC下40 wt%的NaCl/PVA及KCl/PVA的k值从0.2 W/(m·K)增加到0.578 W/(m·K)和0.523 W/(m·K)。提升归因于无机离子晶体在PVA基体中形成了多尺度导热路径，增强了热量传递效率。此外，复合材料还具有较低的介电常数及损耗，高击穿强度(E_b)及一定的光学透明性。

(2) 选用与PVA界面相容性更强的两种易溶于水的有机分子晶体丁二酸和己二酸，通过控制溶液蒸发温度与分子晶体浓度，观察其在PVA中的晶体生长过程并调控结晶形态。结果表明，在溶剂蒸发过程通过动态调控有机分子晶体的形成及对结晶形态及空间分布可构筑不同状态的声子传递网络，实现对PVA导热的调控。例如，30 ^oC下40 wt%含量的丁二酸/PVA与己二酸/PVA的k值分别为0.544 W/(m·K)和0.593 W/(m·K)。同时，复合材料的还具有较低的介电常数及损耗，高E_b及一定的光学透明性。

(3) 采用溶液混合及流延法制备不同共混比的聚乙烯吡咯烷酮(PVP)/PVA共混膜，并采用拉伸取向法与静电纺丝两种手段对共混膜进行取向。研究发现，PVP通过链间氢键及刚性主链结构限制PVA柔性分子链的多尺度松弛行为，链取向及链间作用的协同作用优化了体系多尺度有序结构，从而获得导热及电绝缘良好的聚合物材料。在PVP:PVA=2:8时综合性能达到最佳，如PVP/PVA共混膜、拉伸-取向膜、静电纺丝膜的k值分别为0.48 W/(m·K)、0.8 W/(m·K)、0.87 W/(m·K)，而E_b值分别为115.51 kV/mm、190.11 kV/mm、198.7 kV/mm。

With the rapid development of microelectronics technology towards miniaturization, high integration and high power, the problem of heat accumulation in components has become increasingly prominent. If the accumulated heat cannot be dissipated in a timely and effective manner, the temperature of the device will rise rapidly, which will have a significant impact on its operating speed, accuracy, reliability and service life. Therefore, effective heat dissipation has become the key to ensuring the stable operation and extending the service life of the device, which urgently requires the development of flexible composite materials with high thermal conductivity and high insulation as thermal management materials to achieve rapid heat dissipation in insulating environments. Polyvinyl alcohol (PVA) has become a commonly used polymer material in the field of thermal management materials for microelectronics and power equipment packaging due to its easy processing, excellent insulation performance and good optical transparency. However, the intrinsic thermal conductivity (k value) of PVA is very low, which is difficult to meet the heat dissipation requirements of electronic devices and power equipment packaging in fields that require high insulation and optical transparency.

To address this issue, this study pursued a dual approach: first, by doping inorganic ionic crystals and organic molecular crystals into PVA to induce crystallization, thereby regulating the morphology and spatial distribution of these crystals within the PVA matrix to control thermal conductivity; second, by selecting ligand polymers capable of forming inter-chain hydrogen bonds with PVA to construct blend polymers. This approach leveraged the long-range ordered template effect during orientation and the self-regulating effect of inter-chain hydrogen bonding to achieve molecular chain alignment from the microscale to the mesoscale. This alignment provided efficient phonon transmission pathways while suppressing carrier transport, enabling simultaneous optimization of thermal conductivity and electrical insulation performance. The main research findings are as follows:

(1) Two inorganic ionic crystals, sodium chloride (NaCl) and potassium chloride (KCl), which are easily soluble in water, were selected. By regulating the amount of inorganic salt, temperature, concentration and other conditions, the crystallization and crystal growth processes of different ions in PVA were observed, and the spatial distribution of the crystals in PVA was regulated to construct different forms of phonon transmission pathways. The study found that the evaporation temperature affects the crystal growth kinetics by influencing the evaporation rate of the solution. Understanding the competitive mechanism between the ion crystallization rate and the solvent evaporation rate is conducive to controlling the morphology and spatial distribution of inorganic ionic crystals in the PVA matrix, thereby constructing different phonon paths to regulate the thermal conductivity of PVA. With the increase in the content of inorganic ionic crystals, the k value of the composite material significantly increased. At lower temperatures, ions are more likely to form uniform and ordered heat conduction paths, so the k value of PVA increased significantly. For example, at 30 °C, the k values of 40 wt% NaCl/PVA and KCl/PVA increased from 0.2 W/(m·K) to 0.578 W/(m·K) and 0.523 W/(m·K), respectively. The increase was attributed to the formation of multi-scale heat conduction paths by inorganic ionic crystals in the PVA matrix, enhancing the heat transfer efficiency. In addition, the composite materials also have low dielectric constant and loss, high breakdown strength(E_b) and certain optical transparency.

(2) Two organic molecular crystals, succinic acid and adipic acid, which are easily soluble in water and have stronger interfacial compatibility with PVA, were selected. By controlling the evaporation temperature of the solution and the concentration of the molecular crystals, their crystal growth processes in PVA were observed and the crystallization morphology was regulated. The results showed that during the solvent evaporation process, different states of phonon transmission networks could be constructed by dynamically regulating the formation of organic molecular crystals and their crystallization morphology and spatial distribution, thereby achieving the regulation of the thermal conductivity of PVA. For example, at 30 °C, the k values of 30 wt% succinic acid/PVA and adipic acid/PVA were 0.544 W/(m·K) and 0.593 W/(m·K), respectively. At the same time, the composite materials also have low dielectric constant and loss, high breakdown strength and certain optical transparency.

(3) Different blends of polyvinylpyrrolidone (PVP)/PVA with various blending ratios were prepared by solution mixing and casting methods. The blends were oriented by both tensile orientation and electrospinning. It was found that PVP restricted the multi-scale relaxation behavior of PVA flexible molecular chains through inter-chain hydrogen bonds and rigid main chain structure. The synergistic effect of chain orientation and inter-chain interaction optimized the multi-scale ordered structure of the system, thereby obtaining polymer materials with good thermal conductivity and electrical insulation. The comprehensive performance was the best when the PVP:PVA ratio was 2:8. For example, the k values of PVP/PVA blends, tensile-oriented films, and electrospun films were 0.48 W/(m·K), 0.8 W/(m·K), and 0.87 W/(m·K), respectively, while the E_b values were 115.51 kV/mm, 190.11 kV/mm, and 198.7 kV/mm, respectively.