Numerical Analysis of Effective Permeability of Concrete-Like Material With a Random Three-Phase Mesostructure

Interfacial transition zone (ITZ) is an important component of a concrete-like material. Accurately simulating the ITZ's characteristics of the concrete-like materials is a difficult process in numerical simulation. This article proposed a random three-phase mesostructural modeling method using the incorporation of random aggregate generation, Minkowski sum theory, and polygon union techniques. It was found that this method can better simulate the mesostructure and ITZ characteristics of concrete-like materials. By using this method, a random three-phase mesostructural model had been built for conducting a finite element analysis to investigate the effective permeability parameters of concrete. A good agreement between numerical and experimental results indicates the feasibility of this method in the concrete-like material analysis.

Design of Functionalized Lobed Particles for Porous Self-Assemblies

Colloidal particles fabricated with anisotropic interactions have emerged as building blocks for designing materials with various nanotechnological applications. We used coarse-grained Langevin dynamics simulations to probe the morphologies of self-assembled structures formed by lobed particles decorated with functional groups. We tuned the interactions between the functional groups to investigate their effect on the porosity of self-assembled structures formed by lobed particles with different shapes (snowman, dumbbell, trigonal planar, tetrahedral, square planar, trigonal bipyramidal, and octahedral) at different temperatures. The dumbbell, trigonal planar, and square planar shaped particles, with planar geometries, form self-assembled structures including elongated chains, honeycomb sheets, and square sheets, respectively. The particles with non-planar geometries (tetrahedral, trigonal bipyramidal, and octahedral) self-assemble into random aggregate morphologies. The structures formed by trigonal bipyramidal and octahedral particles exhibit smaller and homogeneous pores compared to the structures formed by trigonal planar and square planar particles. The porosity in self-assembled structures is substantially enhanced by the functionalization of particles.

Supramolecular Interactions in Aromatic Structures for Non-Optical and Optical Chemosensors of Explosive Chemicals

The scientific investigation based on the molecular design of aromatic compounds for high-performance chemosensor is challenging. This is because their multiplex interactions at the molecular level should be precisely determined before the desired compounds can be successfully used as sensing materials. Herein, we report on the molecular design of chemosensors based on aromatic structures of benzene as the organic motif of benzene-1,3,5-tricarboxamides (BTA), as well as the benzene pyrazole complexes (BPz) side chain, respectively. In the case of BTA, the aromatic benzene acts as the centre to allow the formation of π–π stacking for one-dimensional materials having rod-like arrangements that are stabilized by threefold hydrogen bonding. We found that when nitrate was applied, the rod-like BTA spontaneously formed into a random aggregate due to the deformation of its hydrogen bonding to form inactive nitroso groups for non-optical sensing capability. For the optical chemosensor, the aromatic benzene is decorated as a side-chain of BPz to ensure that cage-shaped molecules make maximum use of their centre providing metal-metal interactions for fluorescence-based sensing materials. In particular, when exposed to benzene, Cu-BPz displayed a blue-shift of its original emission band from 616 to 572 nm (Δ = 44 nm) and emitted bright orange to green emission colours. We also observe a different mode of fluorescence-based sensing materials for Au-BPz, which shows a particular quenching mechanism resulting in 81% loss of its original intensity on benzene exposure to give less red-orange emission (λ = 612 nm). The BTA and BPz synthesized are promising high-performance supramolecular chemosensors based on the non-optical and optical sensing capability of a particular interest analyte.