Continuum and atomistic scale computational mechanics for structures with small length scales. With on-demand call to molecular dynamics simulations and scale up to continuum level constitute models, where predictions can be made for laboratory accessible time and length scales.

Material systems including: crystal plasticity in singly/poly crystalline metals, interfacial/grain-boundary mechanics in nanostructured materials, amorphous solids, nanowires, soft materials.

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薄膜材料黏附强度和温度的线性关系

       以二维材料、细胞膜为代表的薄膜材料在生物医药、先进材料以及工程领域有着广泛的应用。薄膜材料的黏附行为将影响它们的性能。日前,中科院力学所、华中科技大学团队在相关研究中取得重要进展。他们发现薄膜材料的黏附行为受到细胞膜表面形貌的影响,因此具有非常高的温度敏感性。相关结果以"The linear-dependence of adhesion strength and adhesion range on temperature in soft membranes"为题发表于固体力学与物理杂志(Journal of the Mechanics and Physics of Solids 132(2019)103697)。 

  该团队通过分子尺度模拟和理论分析,发现软物质薄膜与基体材料的黏附行为与温度相关,这与传统的力学理论有所差异。薄膜材料在垂直表面方向缺少束缚,因此表面存在褶皱。研究人员首先以二维材料石墨烯为研究对象,发现当薄膜与基底相互作用时,其表面波动的幅值与温度成正比,与基底作用强度的1/2次方成反比。这一表面形貌的变化,即为导致粘附行为改变的原因。进一步的分析发现,薄膜与基底材料相互作用强度与温度成线性关系。当温度升高时,表面波动更为剧烈,薄膜与基底材料的粘附强度减弱,但相互作用范围相应增大,如图片所示。 

  由于细胞膜的弯曲刚度与石墨烯近似并且在对于细胞生命活动有重要意义,因此研究人员以细胞膜为研究对象,对该结论进行了进一步的验证,发现细胞膜的黏附行为依然受膜表面形貌的影响,表面的波动扩大了范德华力的作用范围。这样的结论对于理解细胞与外界环境相互作用的温度敏感性有重要作用。 

   图片说明:薄膜材料表面形貌与温度、基底作用强度关系示意图;薄膜的黏附行为与温度的关系。 

  中国科学院力学研究所常正华博士为论文第一作者,魏宇杰研究员为通讯作者,通讯作者还包括华中科技大学杨荣贵教授。该项目得到国家自然科学基金(Grants NO. 11425211),中国科学院战略性先导科技专项(XDB22020200)以及中国科学院"复杂系统力学"卓越创新中心的支持,计算模拟得到中科院超级计算中心支持。

 

Recent Publications

[1] Yanglizhi Li, Luzhao Sun, Zhenghua Chang, ..., Yujie Wei*, Hailin Peng*, Li Lin*, Zhongfan Liu*. Large Single‐Crystal Cu Foils with High‐Index Facets by Strain‐Engineered Anomalous Grain Growth. Advanced Materials, 2020, 32, 2002034.
[2] Shenyou Peng, Yujie Wei*, Huajian Gao*. Nanoscale precipitates as sustainable dislocation sources for enhanced ductility and high strength. PNAS, 2020, 117(10).
[3] Zhenghua Chang, Ronggui Yang*, Yujie Wei*. The linear-dependence of adhesion strength and adhesion range on temperature in soft membranes. Journal of the Mechanics and Physics of Solids, 2019, 132: 103697.
[4] Shenyou Peng, Yujie Wei*, Zhaohui jin,Wei Yang. Supersonic Screw Dislocations Gliding at the Shear Wave Speed. Physical Review Letters, 2019, 122(4).
[5] Zeng XG,Yujie Wei*. The effective fracture strength and fracture toughness of solids with energy dissipation confined to localized strips. International Journal of Plasticity,2019,120:47-63.
[6] Chengqi Sun, Qingyuan Song, Lingling Zhou, Jialong Liu, Yao Wang, Xiaolei Wu, Yujie Wei*. The formation of discontinuous gradient regimes during crack initiation in high strength steels under very high cycle fatigue. International Journal of Fatigue, 2019, 124: 483-492.
[7] Chao Wang, Jici Wen, Fei Luo, Baogang Quan, Hong Li, Yujie Wei*, Changzhi Gu, Junjie Li. Anisotropic expansion and size-dependent fracture of silicon nanotubes during lithiation. Journal of Materials Chemistry A, 2019.
[8] Yujie Wei*, Ronggui Yang*. Nanomechanics of graphene. National Science Review, Volume 6, Issue 2, March 2019, Pages 324–348.
[9] Xiaokun Gu, Yujie Wei*, Xiaobo Yin, Baowen Li*, Ronggui Yang*. Colloquium: Phononic thermal properties of two-dimensional materials. Reviews of Modern Physics, 2018, 90(4): 041002.
[10] Yue Qi, Yunyu Wang, Zhenqian Pang, ..., Yujie Wei*, Jinmin Li*, Zhongfan Liu*. Fast Growth of strain-free AlN on graphene-buffered sapphire. Journal of the American Chemical Society, 2018, 140(38): 11935-11941.

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