Probing the Effects of Nanoscale Architecture on the Mechanical Properties of Hexagonal Silica/Polymer Composite Thin Films

Abstract

We examine the effects of controlling nanoscale architecture on the tensile properties of honeycomb‐structured silica/polymer composite films. The hexagonal films are produced using evaporation‐induced self‐assembly and uniaxially strained using a home‐built tensile testing apparatus. Significant differences in the yield strain, failure strain, and tensile moduli between the axes parallel and perpendicular to the film‐deposition direction are observed for the thinnest films examined and are attributed to anisotropy in the film nanostructure that is further characterized with transmission electron microscopy and atomic force microscopy. For properly oriented composites, these films have tensile moduli comparable to the Young's modulus of bulk silica but exhibit failure strains that are about an order of magnitude larger than those seen in typical bulk‐silica systems. The yielding and failure processes are explored using X‐ray diffraction and optical microscopy and are characterized by irreversible changes in the nanoscale architecture. We show that tuning the nanoscale architecture can provide control over the tensile properties of composites, allowing for materials with combinations of stiffness and elasticity unachievable in the analogous bulk systems.

Fructose‐Derived Hollow Carbon Nanospheres with Ultrathin and Ordered Mesoporous Shells as Cathodes in Lithium–Sulfur Batteries for Fast Energy Storage

“…[23][24][25] Moreover, previous reports on templated oxide materials demonstrated that the ordered porous architecture also provides additional mechanical flexibility, which facilitates volume variations during cycling. [24,26] Conventionally, carbon materials with ordered porous structures, such as CMK-3, are synthesized by the ordered porous hard template-assisted nanocasting method, which produces an inverse porous structure. [27,28] Multiple steps, including impregnation of the carbon source, carbonization, and template removal, are required to obtain the ordered structure.…”

“…Therefore, the ordered structure, in particular, improves the rate performance of electrochemical energy storage devices, such as Li/Na‐ion batteries, supercapacitors, and Li–S batteries . Moreover, previous reports on templated oxide materials demonstrated that the ordered porous architecture also provides additional mechanical flexibility, which facilitates volume variations during cycling …”

A Room-Temperature, Solution Phase Method for the Synthesis of Mesoporous Metal Chalcogenide Nanocrystal-Based Thin Films with Precisely Controlled Grain Sizes

“…Thus, upon treatment with small bidentate ligands, there should be negligible volume contraction. The flexibility of nanoporous networks is also likely to help accommodate any volume change that does occur upon cross-linking …”

Polyethylene–Silica Nanocomposites with the Structure of Semi‐Interpenetrating Networks

“…The combination of the properties of a polymeric matrix and silica makes them attractive as barrier, optical, constructional, and other materials. The methods available for the preparation of the polymer–silica nanocomposites are based on the incorporation of nanoparticles of natural foliated or synthetic silica into a matrix by mixing them with a polymer melt or solution, the successive synthesis of a polymer or silica, or their simultaneous synthesis, with silica being obtained by the sol–gel method. In addition, there are some exotic approaches, such as silica precipitation in polymer plasma …”