[Young Scholar's Forum] Screw dislocation-driven growth of 1D and 2D nanomaterials and their electrochemical applications

2019-11-21

Venue: Room 324, Building No.2, North National Science Park of SCUT, Wushan Campus
Time: November 26, Tuesday, 09:00

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Title I: Screw dislocation-driven growth of 1D and 2D nanomaterials and their electrochemical applications
Speaker: Dr.Liang Hanfeng (King Abdullah University of Science and Technology)
Abstract:
One-dimensional (1D) and two-dimensional (2D) nanostructures have exhibited unique fundamental physical properties and demonstrated promising applications in energy storage and conversion. The challenge in growing anisotropic nanostructures is to break the symmetry of crystal growth to promote the formation of highly anisotropic instead of polyhedral crystals. In this talk, I will discuss a “new” growth mechanism that is fundamentally different from the commonly used metal catalysts-driven growth (such as vapor-liquid-solid, VLS), in which screw dislocations provide the self-perpetuating steps to enable 1D or 2D crystal growth. I will further discuss the generality and significance of this growth mechanism as well as the electrochemical applications of the resulting structures.


Title II: Ferroelectric fluid showing gigantic polarization properties
Speaker: Dr.Tianchuan Haoshi(RIKEN-CEMS)
Abstract:
A liquid crystal (LC) compound bearing a 1,3-dioxane unit in the mesogenic core (DIO) exhibits an anomalously large dielectric permittivity of ca. 104 in a polar nematic phase (NP) with high fluidity unlike conventional LC. In this temperature range of NP phase, no sharp X-ray diffraction peak is observed at any Bragg angles, similar to that for a nematic phase; however, a inhomogeneous sandy texture is observed through a polarizing optical microscopy, unlike that for a conventional nematic phase. Besides, NP phase exhibits polarization switching with a large polarization value, i.e., P = 4.4 μC cm−2, and a parallelogram-shaped polarization–electric field hysteresis loop, which is also observed in ferroelectrics. The heterogeneously aligned DIO molecules in the ground state shows the tendency of a uniform orientation along the applied electric field, a field-induced polarization switching occurs at the same time. Sufficiently larger second-harmonic generation (SHG) activity is also observed in NP phase. Furthermore, SHG interferometry clearly shows the polarization inversion by reversing the applied electric field in NP phase. These results suggest that a unidirectional, ferroelectric-like parallel polar arrangement of the molecules would be generated along the director in NP phase. For a possible model for large polarization behavior in NP phase, we would like to talk on the day of presentation.


Title III:Virus protein cages as building blocks for functional materials
Speaker:Dr.Liu Aijie(
Uppsala University)

Abstract:
The use of protein architectures for bionanotechnology applications is a rapidly emerging field. Protein cages have been widely used as nano-carriers and nano-templates. By mimicking nature, protein cages has provide a platform to mimic and understand enzymatic activity through integration of reaction reagents in the confinement. However, considering the intrinsic properties of virus protein cages, e.g., dynamic structures, surface charge distributions and limited pores etc., the use of protein cage architectures in functional materials has not fully explored yet. In this work, I will introduce plant virus, Cowpea Chlorotic Mottle Virus (CCMV) as building block to construct multifunctional materials. Where the focus is on gold as a catalyst, to further explore its application as a nanoreactor, but also as the construction material for functional films by either cross-linking the protein cages or using them as a template for silica synthesis.



Announced by the School of Molecular Science and Engineering Institues for Soft Matter Science and Technology


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