Silica-Coated Core–Shell Structured Polystyrene Nanospheres and Their Size-Dependent Mechanical Properties

Abstract

The core-shell structured PS/SiO composite nanospheres were synthesized on the basis of a modified Stöber method. The mechanical properties of monodisperse nanospheres were characterized with nanoindentation on the basis of the atomic force microscopy (AFM). The surface morphologies of PS/SiO composite nanospheres was scanned with the tapping mode of AFM, and the force-distance curves were measured with the contact mode of AFM. Different contact models were compared for the analyses of experimental data. The elastic moduli of PS/SiO composite nanosphere (4-40 GPa) and PS nanosphere (∼3.4 GPa) were obtained with the Hertz and Johnson-Kendall-Roberts (JKR) models, respectively, and the JKR model was proven to be more appropriate for calculating the elastic modulus of PS/SiO nanospheres. The elastic modulus of SiO shell gradually approached a constant value (∼46 GPa) with the increase of SiO shell thickness. A core-shell model was proposed for describing the relationship between PS/SiO composite nanosphere's elastic modulus and shell thickness. The mechanical properties of the composite nanospheres were reasonably explained on the basis of the growth mechanism of PS/SiO composite nanospheres, in particular the SiO shell's formation process. Available research data of PS/SiO composite nanospheres in this work can provide valuable guidance for their effective application in surface engineering, micro/nanomanufacturing, lubrication, and so on.

Effect of Bifunctional Montmorillonite on the Thermal and Tribological Properties of Polystyrene/Montmorillonite Nanocomposites

“…The soap-free emulsion polymerization was applied to prepare the PS/OMMT nanocomposites according to previous reports [24,25]. Briefly, a mixture of OMMT (0.6 g, 3.0 wt % based on St), St (20.0 g), DVB (1.8 g) and an auxiliary monomer MAA (1.0 g) was ultrasonicated for 10 min in an ice bath and then magnetically stirred at room temperature for 1 h (Figure 1 (Stage D)).…”

Unpacking the toolbox of two-dimensional nanostructures derived from nanosphere templates

“…The group of Yan turns their attention to the field recently using an atomic force microscope (AFM) with a peakforce quantitative nanoscale mechanical (QNM) mode. [306][307][308] The nano/micromechanical plays a significant role in flexible and stretchable devices, such as the triboelectric nanogenerator. 223 Moreover, integration of the colloidal-based surface patterning with other lithography/patterning methods may be widely applied.…”

Non-spherical abrasives with ordered mesoporous structures for chemical mechanical polishing

“…For example, as previously reported, porous silica abrasives turn out to be a better choice than conventional solid spheres due to their superior surface-flattening and damage-eliminating abilities, which can be attributed to their preferable elastic deformation ability [43,46,47]. In fact, the dependence of E values on porous silica shell thicknesses in the core-mesoporous shell structured composites has been largely vindicated in some literatures [48][49][50]. Moreover, Jauffrès et al [51] concluded employing nanoindentation and finite element model that mesoporous thin silica films with a lattice-ordered porosity exhibit a higher indentation modulus and a more elastic recovery behavior relative to random macroporous ones.…”