Jialiang Chen

Bio: Jialiang Chen is an academic researcher. The author has contributed to research in topics: Hydrogen bond & Graphene. The author has an hindex of 1, co-authored 2 publications receiving 2 citations.

Supramolecular Self-assembly Behaviors of Asymmetric Diblock Copolymer Blends with Hydrogen Bonding Interactions between Shorter Blocks Modelled by Yukawa Potentials

Abstract: We employed the extended self-consistent field theory to investigate the supramolecular self-assembly behaviors of asymmetric diblock copolymer blends (AB/B′C) with hydrogen bonding interactions between shorter B and B′ blocks. The hydrogen bonding interactions are described by Yukawa potentials, where the hydrogen bonding donors and acceptors were modelled as two blocks smeared with opposite screened charges. The hierarchical microstructures with parallelly packed lamellae-in-lamellae (Lam) and 4.8.8 Archimedean tilting pattern (4.8.8) were observed at lower and higher hydrogen bonding density (θ), respectively. The hierarchy of Lam and 4.8.8 were demonstrated by the one- and two-dimensional density profiles and the underlying order of the large-length-scale and small-length-scale microstructures were also clarified. It was found that the 4.8.8 is favorable to the stronger hydrogen bonding density or interactions. As θ increases, the microphase transition from Lam to 4.8.8 occurs at θ=0.34, which is mainly attributed to the optimization of the electrostatic energy and conformational entropy with sacrificing the interfacial energy. This work can provide a new strategy to understand the supramolecular self-assembly as well as the mechanism behind the formation of complex hierarchical microstructures.

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Synthesis of Nickel Spinel Ferrites Nanoparticles Coated with Thermally Reduced Graphene Oxide for EMI Shielding in the Microwave, UV, and NIR Regions.

Abstract: The co-precipitation and in situ modified Hummers’ method was used to synthesize Nickel Spinal Ferrites (NiFe) nanoparticles and NiFe coated with Thermally Reduced Graphene Oxide (TRGO) (NiFe-TRGO) nanoparticles, respectively. By using polyvinyl chloride (PVC), tetrahydrofuran (THF), and NiFe-TRGO, the nanocomposite film was synthesized using the solution casting technique with a thickness of 0.12–0.13 mm. Improved electromagnetic interference shielding efficiency was obtained in the 0.1–20 GHz frequency range. The initial assessment was done through XRD for the confirmation of the successful fabrication of nanoparticles and DC conductivity. The microstructure was analyzed with scanning electron microscopy. The EMI shielding was observed by incorporating a filler amount varying from 5 wt.% to 40 wt.% in three different frequency regions: microwave region (0.1 to 20 GHz), near-infrared (NIR) (700–2500 nm), and ultraviolet (UV) (200–400 nm). A maximum attenuation of 65 dB was observed with a 40% concentration of NiFe-TRGO in nanocomposite film.

Driving forces and molecular interactions in the self-assembly of block copolymers to form fiber-like micelles

Abstract: One-dimensional (1D) nanoscale objects abundant in nature commonly possess hierarchical structures and are generally constructed via bottom-up self-assembly strategies. The unique high aspect ratio morphology of the assembled nanofibrillar materials, such as collagen, cellulose, and silk, together with highly ordered architectures, endows a range of remarkable functionalities in nature. Inspired by this hierarchical building principle, block copolymers (BCPs) have been developed and employed to engineer man-made functional 1D nanostructures and as models to study the self-assembly process. The rapid development of advanced polymerization techniques allows for the precise design of BCPs and the resulting assemblies with intensive studies on distinct structure–property–function relationships. In this Review, we summarize and discuss the formation of fiber-like micelles from the perspectives of fundamental driving forces and molecular interactions involved in the solution self-assembly process. Three main formation mechanisms are highlighted, including covalent bonding, volume exclusion, and crystallization, which are involved in the corresponding domains of coronal, interfacial, and core segments of BCPs. Two spatiotemporal levels of fiber-like assemblies are discussed. In addition, the emerging applications and a general guidance for the rational design of advanced BCPs are proposed in light of the unique traits of fiber-like micelles.

Structure and properties of polymer/two-dimensional nanomaterials studied via molecular dynamics simulation: a review

Abstract: The complicated effects of the 2D filler characteristics on the mechanical, viscoelastic and thermal and electrical conductivity properties of polymer nanocomposites are summarized.