Nanoporous Structures: Smaller is Stronger

Abstract

Nanoporous structures have become the focus of intensive research in recent years owing to their unique applications in mesoscopic physics and chemistry, and potential technological applications, including sensing, catalysis, DNA translocation, and as templates for nanostructure self-assembly. [1][2][3][4][5][6] The study of nanoporous structures such as nanopore-, nanocavity-, and nanochannel-array materials can afford a deep understanding of the new scientific results in such good systems with negative curvature surface. As the number of atoms near the inner surface of nanoporous structures is very large relative to the total number of atoms, the surface effects on the physical and chemical properties can be dominant. It is well known that many physical properties of nanomaterials and nanostructures such as melting temperature, surface free energy, elastic modulus, and cohesive energy show strong size effects. [7][8][9] Nanoporous materials with large internal surface area have been more extensively employed than other nanomaterials as good host materials in nanotechnology. [10] For example, nanoporous structures and nanocavities show a novel sink effect to capture molecules, and the effect can be controlled by tuning the pore size and porosity. [2] Since the lower coordination of atoms of nanoporous structures can lead to the redistribution of electronic charge and change the cohesive energy of single atoms in a matrix, the mechanical responses differ from those of atoms in the bulk counterpart. Additionally, the mechanical applications of nanoporous structures are currently an important subject of much research. Thus, numerous expressions about the porosity dependence of the isotropic elastic modulus have been developed by effective medium theory. [11][12] The effective elastic modulus is suitable for describing the mechanical properties of nanoporous structures. In general, the effective elastic modulus of porous material is expressed as the elastic module of the matrix and the porosity inclusion in the materials. [13] However, the surface elasticity of nanostructures is different from the bulk, which is generalized by the Young-Laplace equation based on the mechanical equilibrium principle. [14] Dual et al. pointed out that the stiffness of nanoporous materials may be made to exceed those of the nonporous counterpart bulk by satisfying certain surface modifications. [15] In fact, nanoporous structures are similar with nanocavities with negative curvature of inner surface in matrix.Sentence ambiguous. Please rephrase. The large innersurface energy can lead to the effective elastic modulus of the surface with a negative curvature being larger than that of the plane case. [16] Importantly, the inner skin of nanocavities will undergo local hardening owing to the local bond stiffening around nanocavities when the void size becomes small. [16][17] However, there are not any quantitative theories to predict the mechanical responses of nanoporous structures when the cylindrical pore size is in the range of several ...

Size Dependent Debye Temperature and Total Mean Square Relative Atomic Displacement in Nanosolids under High Pressure and High Temperature

“…1,2 Thus, the surface effect of nanosolids plays a crucial role in their relevant physical and chemical properties. Also, the number of atoms constituting individual particles is an important factor in determining the crystalline structure and energy state of a material.…”

Band gap tailoring and enhanced ferromagnetism in Yb doped SrWo4 scheelite structured system

“…Further, the strain induced by dopant in 1 % Yb doped compound was compressive. This may be due to the influence of synthesis process and surface morphology of the compounds [50]. Various models such as Zener pinning and Corner point pinning have been proposed to explain of anomalous grain growth in materials.…”

“…The absorption spectra of 1 % Yb doped sample reveals influence of crystallite size, lattice strain and shape of the particles over the optical absorption behaviour of materials. The lattice strain leads to surface or interface trapping and localization of charge, energy and mass on the surface [50]. So it was identified that the surface morphology plays vital role on defining optical properties of materials.…”

Hybrid Solar Cells: Materials, Interfaces, and Devices

“…Nanoporous structures have received increasing attention due to their unique applications in catalysis reactions, DNA translocation, hybrid solar cells, and as templates for nanostructure self-assembly [13]. Nanoporous structures are comprised of a multitude of nanopores, nanocavities, or nanochannel arrays where the pore size and porosity can be tuned at will at the nanoscale.…”