采用真空浸渗法,成功地将硬脂酸填充到碳纳米管(CNTs)空管内,得到CNTs/硬脂酸纳米相变胶囊材料。差示扫描量热分析表明,硬脂酸填充CNTs后,熔点下降了2.85℃,硬脂酸在CNTs内的体积填充度为31.9%。采用分子动力学方法深入研究硬脂酸在CNTs受限空间内的热性质。结果表明,在CNTs的纳米受限空间作用下,硬脂酸分子在CNTs内呈有序的环状分布,与CNTs的管壁距离保存在0.37nm。与纯硬脂酸相比,CNTs/硬脂酸的熔点降低,自扩散系数增加,导热系数比空CNTs下降32%～41%,为纯硬脂酸的117～159倍。
With a vacuum infiltration method,stearic acid was successfully infiltrated into the inner space of carbon nanotubes (CNTs),resulting in nano-encapsulated phase change materials (PCMs).DSC results indicated that the melting temperature of stearic acid decreased by 2.85℃ and the filling degree of stearic acid inside the CNTs was 31.9%.To deep understand the interaction between stearic acid and CNTs,molecular dynamics (MD) method was performed.The results showed that the stearic acid molecules exhibited an orderly circular distribution near the inner wall of the CNTs and kept a distance at 0.37nm with the wall of CNTs in the effect of the nanoconfined environment.Compared with pure stearic acid,the melting temperature of PCMs decreased and the diffusion coefficient increased.The thermal conductivity of PCMs was 32%～41% lower than that of empty CNTs and 117～159 times higher than that of the stearic acid matrix.
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基金资助
国家自然科学基金(51206071);中国博士后科学基金资助项目(2013M542125);湖南省自然科学基金项目(2019JJ40284)
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