Anh Son Hoang

Bio: Anh Son Hoang is an academic researcher from Vietnam Academy of Science and Technology. The author has contributed to research in topics: Metal & Germination. The author has an hindex of 2, co-authored 2 publications receiving 71 citations.

Electrical conductivity and electromagnetic interference shielding characteristics of multiwalled carbon nanotube filled polyurethane composite films

Abstract: Multiwalled carbon nanotubes (MWCNTs) were homogeneously dispersed in a pure polyurethane resin by grinding in a planetary ball mill. The structure and surface morphology of the MWCNTs and MWCNT/polyurethane composites were studied by filed emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) methods. The electrical conductivity at room temperature and electromagnetic interference (EMI) shielding effectiveness (SE) of the composite films with different MWCNT loadings were investigated and the measurement of EMI SE was carried out in a frequency range of 8–12 GHz (X-band). The experimental results show that with a low MWCNT concentration the composite films could achieve a high conductivity and their EMI SE has a strong dependence on MWCNT content. For the composite films with 22 wt% of MWCNTs, the EMI SE attained an average value of 20 dB, so that the shielding effect reduced the penetrating power to 1%.

Carbon nanotubes materials and their application to guarantee safety from exposure to electromagnetic fields

Abstract: Multi-walled carbon nanotubes (MWCNTs)-filled epoxy composites and poly(methyl methacrylate) (PMMA) coatings were prepared by mechanical grinding with the use of a planetary ball mill. Electromagnetic interference shielding effectiveness, electromagnetic absorption and reflection properties of the materials were investigated. With MWCNTs loadings higher than 20 wt%, epoxy/MWCNTs composites and PMMA/MWCNTs coatings also exhibited the full capability of shielding from more than 99% electromagnetic radiation at the 100 MHz–14 GHz frequency range.

Evaluation of metal nano-particles as growth promoters and fungi inhibitors for cereal crops

Abstract: Abstract Background Nano-particles of metals can be routinely synthesized. The cereal seeds treatment with the particles can improve early growth and crop production. Moreover, the treatment is robust and economical. Methods Metal (Fe 0 , Cu 0 , Co 0 ), zinc oxide (ZnO) and chitosan-stabilized silver nano-particles were synthesized and applied to cereal seeds. The germination rate, early plant development and inhibition effects on pathogenic fungi were quantified. Results It was found that all nano-particles had a positive effect on the development of healthy cereal seedlings. In particular, the length of the above-ground part of the seedlings was increased by 8–22%. The highest inhibition effect was observed on Helminthosporium teres with the application of Co 0 and chitosan-Ag. Pre-sowing treatment with metal nano-particles reduced the number of infected grains by two times for wheat and 3.6 times for barley. The application also increases the chlorophylls and carotenoids in both uninfected and infected seedlings. Conclusions The results demonstrated a robust application of nano-particles in improving cereal production. Graphical Abstract

Evaluation of metal nano-particles as growth promoters and fungi inhibitors for cereal crops

Abstract: Abstract Background Nano-particles of metals can be routinely synthesized. The cereal seeds treatment with the particles can improve early growth and crop production. Moreover, the treatment is robust and economical. Methods Metal (Fe 0 , Cu 0 , Co 0 ), zinc oxide (ZnO) and chitosan-stabilized silver nano-particles were synthesized and applied to cereal seeds. The germination rate, early plant development and inhibition effects on pathogenic fungi were quantified. Results It was found that all nano-particles had a positive effect on the development of healthy cereal seedlings. In particular, the length of the above-ground part of the seedlings was increased by 8–22%. The highest inhibition effect was observed on Helminthosporium teres with the application of Co 0 and chitosan-Ag. Pre-sowing treatment with metal nano-particles reduced the number of infected grains by two times for wheat and 3.6 times for barley. The application also increases the chlorophylls and carotenoids in both uninfected and infected seedlings. Conclusions The results demonstrated a robust application of nano-particles in improving cereal production. Graphical Abstract

Research on sulfate bacteriostatic effect of some metal nanos

Abstract: Sulfate-reducing bacteria (Desulfomicrobium baculatum) is a group of anaerobic bacteria capable of producing H2S gas, which sours crude oil, corrodes metal equipment, pipeline systems, and even forms biofilms that cause blockages reservoir, reducing the reception capacity of pumped water in oil and gas exploitation. Currently, the biocides are mainly aldehydes or cyclic amines combined with cationic active substances, which are very toxic to humans and the environment. The development of materials technology has created new nano-sized materials that are capable of replacing traditional biocides and are environmentally friendly. This study has shown that silver and copper metal nanoparticles with an average size of 50 nm and concentration from 500 ppm can inhibit and kill both sulfate-reducing bacteria strains swimming and adhering in the water at normal and high temperature conditions.

Recent advances in electromagnetic interference shielding properties of metal and carbon filler reinforced flexible polymer composites: A review

Abstract: The rapid proliferation and elevated usage of electronic devices have led to a meteoritic rise in electronic pollutions such as electronic noise, electromagnetic interference (EMI) and radiofrequency interference (RFI) which leads to improper functioning of electronic devices. Metals and their alloys can serve as the best EMI shielding materials but their heavy weight, high cost and low corrosion resistance have limited their applications in EMI shielding. The emergence of flexible polymer composites have substituted the metal and metal alloy based EMI shielding materials due to their unique features such as light weight, excellent corrosion resistance, superior electrical, dielectric, thermal, mechanical and magnetic properties that are highly useful for suppressing the electromagnetic noises. In this review article, the EMI shielding effectiveness of flexible polymer composites comprising of metals and various forms of carbon nanofillers such as carbon black, carbon nanofibers, carbon nanotubes, graphite, graphene, graphene oxide, graphene nanosheets, graphene nanoribbons and graphene nanoplatelets have been deeply reviewed.

Layer-by-Layer Assembly of Cross-Functional Semi-transparent MXene-Carbon Nanotubes Composite Films for Next-Generation Electromagnetic Interference Shielding

Abstract: Lightweight, flexible, and electrically conductive thin films with high electromagnetic interference (EMI) shielding effectiveness are highly desirable for next-generation portable and wearable electronic devices. Here, spin spray layer-by-layer (SSLbL) to rapidly assemble Ti3C2Tx MXene-carbon nanotube (CNT) composite films is shown and their potential for EMI shielding is demonstrated. The SSLbL technique allows strategic combinations of nanostructured materials and polymers providing a rich platform for developing hierarchical architectures with desirable cross-functionalities including controllable transparency, thickness, and conductivity, as well as high stability and flexibility. These semi-transparent LbL MXene-CNT composite films show high conductivities up to 130 S cm−1 and high specific shielding effectiveness up to 58 187 dB cm2 g−1, which is attributed to both the excellent electrical conductivity of the conductive fillers (i.e., MXene and CNT) and the enhanced absorption with the LbL architecture of the films. Remarkably, these values are among the highest reported values for flexible and semi-transparent composite thin films. This work could offer new solutions for next-generation EMI shielding challenges.

Ultralow percolation threshold and enhanced electromagnetic interference shielding in poly(L-lactide)/multi-walled carbon nanotube nanocomposites with electrically conductive segregated networks

Abstract: Electrically conductive segregated networks were built in poly(L-lactide)/multi-walled carbon nanotube (PLLA/MWCNT) nanocomposites without sacrificing their mechanical properties via simply choosing two different PLLA polymers with different viscosities and crystallinities. First, the MWCNTs were dispersed in PLLA with low viscosity and crystallinity (L-PLLA) to obtain the L-PLANT phase. Second, the PLLA particles with high viscosity and crystallinity (H-PLLA) were well coated with the L-PLANT phase at 140 °C which was below the melting temperature of H-PLLA. Finally, the coated H-PLLA particles were compressed above the melting temperature of H-PLLA to form the PLLA/MWCNT nanocomposites with segregated structures. The morphological observation showed the successful location of MWCNTs in the continuous L-PLLA phase, resulting in an ultralow percolation threshold of 0.019 vol% MWCNTs. The electrical conductivity and the electromagnetic interference (EMI) shielding effectiveness (SE) of the composites with the segregated structure are 25 S m−1 and ∼30 dB, showing three orders and 36% higher than that of the samples with a random distribution of MWCNTs with 0.8 vol% of MWCNT loading, respectively. High-performance electromagnetic interference (EMI) shielding was also observed mainly dependent on the highly efficient absorption shielding, which can be achieved by the densely continuous MWCNT networks and the abundant interfaces induced by the segregated structures. Furthermore, the composites with segregated structures not only showed higher Young's modulus and tensile strength than the corresponding conventional composites, but also maintained high elongation at break because of the continuous and dense MWCNT networks induced by the segregated structures and the high interfacial interaction between H-PLLA and L-PLLA.