scholarly journals Electrophoretic Deposition of Aged and Charge Controlled Colloidal Copper Sulfide Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 133
Author(s):  
Yoonsu Park ◽  
Hyeri Kang ◽  
Wooseok Jeong ◽  
Hyungbin Son ◽  
Don-Hyung Ha
Keyword(s):  
Electrophoretic Deposition ◽  
Building Blocks ◽  
Colloidal Nanoparticles ◽  
Surface Charges ◽  
Interparticle Interactions ◽  
Sem Images ◽  
Charge Formation ◽  
Surface Ligands ◽  
Charge Control ◽  
Controllable Parameter

Colloidal nanoparticles (NPs) have been recently spotlighted as building blocks for various nanostructured devices. Their collective properties have been exhibited by arranging them on a substrate to form assembled NPs. In particular, electrophoretic deposition (EPD) is an emerging fabrication method for such nanostructured films. To maximize the benefits of this method, further studies are required to fully elucidate the key parameters that influence the NP deposition. Herein, two key parameters are examined, namely: (i) the aging of colloidal NPs and (ii) the charge formation by surface ligands. The aging of Cu2-xS NPs changes the charge states, thus leading to different NP deposition behaviors. The SEM images of NP films, dynamic light scattering, and zeta potential results demonstrated that the charge control and restoration of interparticle interactions for aged NPs were achieved via simple ligand engineering. The charge control of colloidal NPs was found to be more dominant than the influence of aging, which can alter the surface charges of the NPs. The present results thus reveal that the charge formation on the colloidal NPs, which depends on the surface ligands, is an important controllable parameter in EPD.

scholarly journals Effects of Synthetic Procedures and Postsynthesis Incubation pH on Size, Shape, and Antibacterial Activity of Copper (I) Oxide Nanoparticles

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Vinh Tien Nguyen ◽  
Khanh Son Trinh
Keyword(s):  
Antibacterial Activity ◽  
High Surface ◽  
Size Variation ◽  
Reaction Rates ◽  
Bacterial Suspension ◽  
Oxide Nanoparticles ◽  
Surface Charges ◽  
Fast Reaction ◽  
Sem Images ◽  
Etching Effect

Copper (I) oxide nanoparticles (Cu2O NP) were synthesized by reducing CuSO4 with glucose in the presence of polyvinyl alcohol as a capping agent. We used three different synthetic procedures with a fast reaction (procedure 1p), a fast-then-slow reaction (procedure 2p), and a slow-then-fast reaction (procedure 3p). The reaction rates were controlled by changing the temperature and the speed of adding reagents. The synthesized Cu2O NP were subsequently incubated for 24 h in a pH 6 solution (Cu2O NP6) or a pH 8 solution (Cu2O NP8) at 5°C. XRD and SEM images analysis revealed that the 1p procedure produced smaller NP, while the 2p procedure produced larger but more uniform NP. The 3p procedure produced the largest NP with a higher size variation. The 24-hour acidic postsynthesis incubation resulted in an etching effect, which reduced the size and size variation of Cu2O NP6. To evaluate the antibacterial activity, E. coli suspensions were mixed with the obtained Cu2O NP (32, 96, or 160 ppm) for different time intervals (1 or 24 h) and then grown on Petri dishes at 37°C for 24 h. Higher doses, smaller sizes of Cu2O NP, and longer contact times with the bacterial suspension resulted in higher inactivation efficiencies. Cu2O NP6 showed higher antibacterial effects at low doses, possibly due to the etching effect and the positive surface charge. Increasing the Cu2O doses from 32 to 96 and 160 ppm noticeably increased the antibacterial effect of the Cu2O NP8, but not significantly for Cu2O NP6. We suggested that the Cu2O NP6 suffered from agglomeration at high doses due to their high surface activity and low surface charges.

Physicochemical Characterization of α-, β-, and γ-Cyclodextrins Bioesterified with Decanoate Chains Used As Building Blocks of Colloidal Nanoparticles

2011 ◽  
Vol 12 (8) ◽  
pp. 3031-3038 ◽  
Author(s):  
Luc Choisnard ◽  
Annabelle Gèze ◽  
Cécile Vanhaverbeke ◽  
Josias B. G. Yaméogo ◽  
Jean-Luc Putaux ◽  
...  
Keyword(s):  
Physicochemical Characterization ◽  
Building Blocks ◽  
Colloidal Nanoparticles

Fabrication of Barium Titanate Inverse Opals by Sol-Gel Electrophoretic Deposition Process

2010 ◽  
Vol 434-435 ◽  
pp. 247-252 ◽  
Author(s):  
Bo Li ◽  
Jin Qing Wang ◽  
Rei Fujiwara ◽  
Makoto Kuwabara ◽  
Ming Fu ◽  
...  
Keyword(s):  
Barium Titanate ◽  
Photonic Crystals ◽  
Electrophoretic Deposition ◽  
Sol Gel ◽  
Deposition Process ◽  
Visible Range ◽  
Face Centered Cubic ◽  
Sem Images ◽  
Inverse Opals ◽  
Opal Template

Barium titanate (BTO) inverse opal photonic crystals were fabricated by a process of self-assembly of polystyrene opal template in combination with electrophoretic deposition (EPD) of nanoparticles from BTO suspension. In this process, stable monodispersed suspension of BTO nanoparticles was prepared by dispersing BTO gel into a mixed solvent of 2-methoxyethanol and acethylacetone. Then the BTO nanoparticles were infilled into the interstices of the opal template formed by monodisperse polystyrene microspheres by electrophoretic deposition, and then polystyrene template was removed by calcining the specimen at a final temperature of 500oC. SEM images show that the inverse opals possess face-centered cubic (fcc) structure with center to center distant of the air spheres 310 nm. A photonic bandgap in the visible range is observed from reflection spectra of the sample. Such BTO inverse opals as photonic crystals should be useful in device applications.

scholarly journals DNA-mediated engineering of multicomponent enzyme crystals

2015 ◽  
Vol 112 (15) ◽  
pp. 4564-4569 ◽  
Author(s):  
Jeffrey D. Brodin ◽  
Evelyn Auyeung ◽  
Chad A. Mirkin
Keyword(s):  
Gold Nanoparticles ◽  
Protein Interactions ◽  
Building Blocks ◽  
Inorganic Nanoparticles ◽  
Protein Protein Interactions ◽  
Dna Interactions ◽  
Interparticle Interactions ◽  
Crystalline Materials ◽  
Catalytically Active ◽  
Surface Chemistries

The ability to predictably control the coassembly of multiple nanoscale building blocks, especially those with disparate chemical and physical properties such as biomolecules and inorganic nanoparticles, has far-reaching implications in catalysis, sensing, and photonics, but a generalizable strategy for engineering specific contacts between these particles is an outstanding challenge. This is especially true in the case of proteins, where the types of possible interparticle interactions are numerous, diverse, and complex. Herein, we explore the concept of trading protein–protein interactions for DNA–DNA interactions to direct the assembly of two nucleic-acid–functionalized proteins with distinct surface chemistries into six unique lattices composed of catalytically active proteins, or of a combination of proteins and DNA-modified gold nanoparticles. The programmable nature of DNA–DNA interactions used in this strategy allows us to control the lattice symmetries and unit cell constants, as well as the compositions and habit, of the resulting crystals. This study provides a potentially generalizable strategy for constructing a unique class of materials that take advantage of the diverse morphologies, surface chemistries, and functionalities of proteins for assembling functional crystalline materials.

Development of Photocatalytic Conversion of Glucose to Value-Added Chemicals by Supported-TiO2 Photocatalysts

2016 ◽  
Vol 839 ◽  
pp. 39-43
Author(s):  
Kamonchanok Roongraung ◽  
Navadol Laosiripojana ◽  
Surawut Chuangchote
Keyword(s):  
Photocatalytic Activity ◽  
Formic Acid ◽  
Gluconic Acid ◽  
Energy Resource ◽  
Value Added ◽  
Building Blocks ◽  
Microwave Method ◽  
Chemical Production ◽  
Sem Images ◽  
Simple Method

Biomass is an important renewable energy resource, which is used to replace the petroleum to produce chemicals. Glucose is a monomer of cellulose, which is the main component of biomass. In this work, conversions of glucose to value-added chemical by a simple method have been reported. TiO2 photocatalysts were fabricated by sol-microwave method. Value-added chemical production was successfully carried out via photocatalytic conversion of glucose with TiO2 photocatalysts. Arabinose, xylitol, gluconic acid, and formic acid were produced with photocatalytic reaction of TiO2 under UVA irradiation. The value-added products (gluconic acid, arabinose, and xylitol) can generally be further used as building blocks for biorefinery production, pharmaceutical production, and food industry. In the conventional sol-microwave method, the agglomeration of fabricated TiO2 particle was a limitation of photocatalytic activity. Therefore, the modification of TiO2 fabrication by use of zeolite as a TiO2 support was applied to increase efficiency of photocatalytic conversion of glucose and its selectivity. The effect of TiO2 dosage on zeolite (TiO2/zeolite) on photocatalytic activity and yield of products was monitored. The results from scanning electron microscopy (SEM) images indicated that zeolite supporter reduced agglomeration of spherical TiO2 particles. The well distribution of TiO2 particles on surface of zeolite particles could be observed in 15%TiO2/zeolite. It was found that the highest photocatalytic conversion of glucose (77.3%) was obtained from the use of 15%TiO2/zeolite as photocatalyst. The yields of gluconic acid, arabinose, xylitol, and formic acid were 8.6, 26.0, 3.7, and 33.89%, respectively.

scholarly journals Fabrication and Characterization of Ag-Sr Doped Hydroxyapatite/chitosan Coatings Deposited on 316L SS via Electrophoretic Deposition

2020 ◽  
Author(s):  
Muhammad Wahaj ◽  
Usama Saleem ◽  
Farasat Iqbal ◽  
Muhammad Yasir ◽  
Abdul Wadood ◽  
...  
Keyword(s):  
Electrophoretic Deposition ◽  
Deposition Time ◽  
Composite Coatings ◽  
Gram Negative Bacteria ◽  
Sem Images ◽  
Hydrophilic Nature ◽  
Deposition Voltage ◽  
Orthopedic Applications ◽  
Chitosan Composite

In this study, silver-strontium doped hydroxyapatite (AgSr-HA)/chitosan composite coatings were deposited on stainless steel (SS) substrate via electrophoretic deposition (EPD) technique. The EPD parameters such as the concentration of Ag Sr-HA particles in the suspension, applied voltage and deposition time were optimized on by the Taguchi Design of Experiment (DoE) approach. DOE approach elucidated that the “best” coating was obtained at; the deposition voltage of 20V, deposition time of 7 minutes, and at 5 g/L of Ag Sr-HA particles in the suspension. The optimum coatings were characterized by using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. SEM images confirmed the deposition of chitosan/Ag Sr-HA on the SS substrate. The wettability studies indicated the hydrophilic nature of the chitosan/Ag Sr-HA coatings, which confirmed the suitability of the developed coatings for orthopedic applications. The average surface roughness of the chitosan/Ag Sr-HA coatings was in a suitable range for the attachment of bone marrow stromal cells. Chitosan/Ag Sr-HA coatings showed a potent antibacterial effect against the Gram-Positive and Gram-negative bacteria.

Optical anisotropy and sign reversal in layer-by-layer assembled films from chiral nanoparticles

2016 ◽  
Vol 191 ◽  
pp. 141-157 ◽  
Author(s):  
Zhumei Liang ◽  
Kalil Bernardino ◽  
Jishu Han ◽  
Yunlong Zhou ◽  
Kai Sun ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Optical Activity ◽  
Metallic Nanoparticles ◽  
Density Functional ◽  
Structural Changes ◽  
Building Blocks ◽  
Layer By Layer ◽  
Semiconductor Films ◽  
Surface Ligands ◽  
Circular Dichroïsm

Chiral anisotropy and related optical effects at the nanoscale represent some of the most dynamic areas of nanomaterials today. Translation of optical activity of chiral semiconductor and metallic nanoparticles (NPs) into optoelectronic devices requires preparation of thin films from chiral NPs on both flat and curved surfaces. In this paper we demonstrate that chiral NP films can be made via layer-by-layer assembly (LBL) using negatively charged chiral CdS NPs, stabilized by d- and l-cysteine and positively charged polyelectrolytes, as building blocks. LBL coatings from NPs combine simplicity of preparation and strong optical activity. Circular extinction measurements using circular dichroism instruments indicate that the film possess four chiroptical bands at 280, 320, 350, and 390 nm. The latter two bands at 390 and 350 nm are associated with the band gap transitions (chiral excitons), while the former two are attributed to transitions involving surface ligands. When NPs are assembled in LBL films, the rotatory activity and the sign for circular extinction associated with the electronic transition in the inorganic core of the NPs is conserved. However, this is not true for circular extinction bands at short wavelengths: the sign of the rotatory optical activity is reversed. This effect is attributed to the change of the conformation of surface ligands in the polyelectrolyte matrix, which was confirmed both by semi-empirical and density functional (DFT) quantum mechanical calculations. Circular dichroism spectra calculated using a DFT algorithm closely match the experimental spectra of CdS NPs. These findings indicate that the spectroscopic methods sensitive to chirality of the surface ligands can be used to investigate fine structural changes in the surface layer of nanocolloids. Strong rotatory optical activity of nanostructured semiconductor films opens the possibilities for new polarization-based optical devices.

Preparation and Characterization of Copolymerized Aminohexylaminomethyl/Phenylsilsesquioxane Microparticles

2012 ◽  
Vol 182-183 ◽  
pp. 114-117 ◽  
Author(s):  
Hao Wang ◽  
Xiu Feng Wang ◽  
Cheng Long Yu
Keyword(s):  
Building Blocks ◽  
Inorganic Materials ◽  
Potential Utility ◽  
Ordered Structure ◽  
Sem Images ◽  
Molar Ratios ◽  
Tetraethylammonium Hydroxide ◽  
Ft Ir ◽  
Xrd Patterns

Poly (aminohexylaminomethyl/phenyl) silsesquioxane (PAHAMPSQ) microparticles with diameter of 350 nm were synthesized by the hydrolytic condensation of aminohexylaminomethyltriethoxysilane (AHAMTES) and phenyltriethoxysilane (PTES) in the presence of H2O by using tetraethylammonium hydroxide (TEAOH) catalysts. PAHAMPSQ containing both aminohexylaminomethyl and phenyl groups were confirmed from FT-IR, TGA. XRD patterns indicate that a certain ordered structure existed in PAHAMPSQ molecules. Contents of amino of PAHAMPSQ were determined by elemental analysis. SEM images show both granular and flake exist in PAHAMPSQ microparticles. Yield of PAHAMPSQ in different AHAMTES/PETS molar ratios was about 80%. PAHAMPSQ offers the potential utility as building blocks for divers and novel organic/inorganic materials.

Sign in / Sign up

Export Citation Format

Share Document