热噪声与结构参数对聚酰亚胺热输运特性的 影响研究

The miniaturization and efficient thermal management of high-power and high-precision electronic devices are taken as the research requairments. Microscopic thermal transport mechanisms of polyimide and graphene/polyimide interfacial materials under extreme heat flux conditions are investigated. Molecular dynamics models with multiple density gradients，variable chain lengths and compression lengths are established，and nonlinear coupling effects of density，chain length，compression length and heat flux density are systematically analyzed combined with the reverse non-equilibrium molecular dynamics method. Results show that thermal conductivity is significantly improved with the increase of density， and a 13-order-of-magnitude increase in thermal conductivity is obtained for the 2. 2 g/cm³ system under a 1 GW/m² heat source，which verifies that interfacial thermal resistance dominates the heat transfer process. Energy fluctuations are suppressed by molecular chain entanglement when the chain length exceeds 15 monomers，and the total energy fluctuation range of the long-chain system is reduced by 57% compared with that of the system with 3 to 5 monomers. An optimal regulation window for compression length is proved to effectively inhibit the nonlinear growth of temperature gradient . The interface reorganization mechanism induced by heat flux density is revealed，and the collaborative optimization law of long-chain relaxation dynamics and compression densification is clarified，which provides new approaches for micro-nano scale thermal transport regulation in extreme thermal management scenarios.