title: Size Dependent Mechanical Properties of Monolayer Densely Arranged Polystyrene Nanospheres.
abstract: In contrast to macroscopic materials, the mechanical properties of polymer nanospheres show fascinating scientific and application values. However, the experimental measurements of individual nanospheres and quantitative analysis of theoretical mechanisms remain less well performed and understood. We provide a highly efficient and accurate method with monolayer densely arranged honeycomb polystyrene (PS) nanospheres for the quantitatively mechanical characterization of individual nanospheres on the basis of atomic force microscopy (AFM) nanoindentation. The efficiency is improved by 1-2 orders, and the accuracy is also enhanced almost by half-order. The elastic modulus measured in the experiments increases with decreasing radius to the smallest nanospheres (25-35 nm in radius). A core-shell model is introduced to predict the size dependent elasticity of PS nanospheres, and the theoretical prediction agrees reasonably well with the experimental results and also shows a peak modulus value.
authors.affiliation: State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, China.|Sicence and Technology on Surface Physics and Chemistry Laboratory , Mianyang 621908, Sichuan, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Huang
authors.affiliation: School of Chemistry, Dalian University of Technology , Dalian 116024, Liaoning, China.
authors.forename: Lijing
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Tsinghua University , Beijing 100084, China.
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, China.
authors.forename: Guoxin
authors.initials: G
authors.lastname: Xie