液晶弹性体温度自适应润湿性表面沸腾特性研究

doi:10.11949/0438-1157.20251059

摘要/Abstract

摘要：

沸腾传热是解决高功率器件散热问题的有效途径之一，然而沸腾传热各阶段对表面润湿特性的需求不同，亟需一种能根据沸腾阶段自主调整润湿特性的表面。利用两步交联法制备了二硫键液晶弹性体材料，将其与铜基底复合，并在其上热压形成微结构，借助液晶弹性体材料的形状记忆功能以及微结构对表面润湿性的影响，制备了温度自适应润湿性表面，实现了接触角从低温96°到高温74°到的转变。通过实验系统研究了不同温度和热通量下自适应润湿性表面的沸腾特性，包括气泡和液体行为及沸腾曲线。结果表明，低热通量下，自适应润湿表面促进气泡成核并降低过热度；高热通量下，表面增强液体补充并延迟干涸，提高临界热通量。与光滑液晶弹性体表面相比，传热系数最高提高6.5%。验证了自适应表面调控沸腾传热的可行性。

关键词: 弹性, 聚合物, 复合材料, 润湿性, 气液两相流, 沸腾, 传热

Abstract:

Boiling heat transfer is one of the most effective approaches for addressing thermal management challenges in high-power devices. However, different stages of the boiling process impose distinct requirements on surface wettability, creating an urgent need for surfaces capable of adaptively regulating their wettability in response to boiling conditions. A disulfide bond-based liquid crystal elastomer was synthesized using a two-step crosslinking method, then integrated with a copper substrate. Microstructures were formed on the surface through hot-pressing. By leveraging the shape-memory effect of the liquid crystal elastomer material together with the influence of microstructures on surface wettability, a temperature-adaptive wettability surface was fabricated, enabling a tunable contact angle from 96° at low temperature to 74° at high temperature. An experimental system was employed to investigate the boiling characteristics of this adaptive surface under varying temperatures and heat fluxes, focusing on bubble dynamics, liquid replenishment, and boiling curves. The results indicate that at low heat fluxes, the adaptive surface promotes bubble nucleation and reduces superheat; while at high heat fluxes, it enhances liquid supply and delays dryout, thereby increasing the critical heat flux. Compared with the smooth liquid crystal elastomer surface, the adaptive surface achieved up to a 6.5% enhancement in the heat transfer coefficient, the feasibility of regulating boiling heat transfer using an adaptive surface was verified.

Key words: elasticity, polymers, composites, wettability, gas-liquid two-phase flow, boiling, heat transfer

中图分类号:

TK 124

陈帅, 胡彦伟, 刘子赫, 加少坤. 液晶弹性体温度自适应润湿性表面沸腾特性研究[J]. 化工学报, DOI: 10.11949/0438-1157.20251059.

Shuai CHEN, Yanwei HU, Zihe LIU, Shaokun JIA. Study on boiling characteristics of liquid crystal elastomer surfaces with thermally adaptive wettability[J]. CIESC Journal, DOI: 10.11949/0438-1157.20251059.

图/表 16

图1 基于二硫键的液晶弹性体的合成路线

Fig.1 Synthetic route of disulfide-based liquid crystal elastomers

图2 温度自适应润湿性表面制备流程图

Fig.2 Fabrication process of temperature-adaptive wettability surface

图3 实验系统示意图

Fig.3 Schematic diagram of the experimental system

图4 实验段示意图

Fig.4 Schematic diagram of the experimental section

图5 产物的1H NMR图

Fig.5 1H NMR spectrum of the product

图6 产物的FTIR图

Fig.6 FTIR spectrum of the product

图7 热响应液晶弹性体的DSC升温曲线

Fig.7 DSC heating curve of the thermo-responsive liquid crystal elastomer

图8 液晶弹性体形变图

Fig.8 Shape deformation of the liquid crystal elastomer

图9 样品表面观测图

Fig.9 Surface observation of the sample

图10 样品自适应测试图

Fig.10 Adaptive performance test of the sample

图11 光滑铜片的沸腾实验结果对比图

Fig.11 Comparison of Boiling Experimental Results on Smooth Copper Surfaces

图12 光滑表面的沸腾气泡运动图

Fig.12 Bubble dynamics on a smooth surface during boiling

图13 光滑液晶表面的沸腾气泡图

Fig.13 Boiling bubble pattern on a smooth liquid crystal surface

图14 自适应表面的沸腾气泡图

Fig.14 Boiling bubble diagram of adaptive surfaces

图15 光滑和自适应表面的沸腾曲线图

Fig.15 Boiling curves of smooth and adaptive surfaces

图16 光滑和自适应表面的传热系数曲线

Fig.16 HTC of smooth and adaptive surfaces

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