Papers by Keyword: Zeta-Potential

Abstract: Brush scrubbing is a well-known post CMP cleaning process. Interaction between PVA brush and the particles removed during the process must be considered while designing a cleaning process. In this work, the effect of cleaning solution pH was investigated in terms of particle removal from the wafer and subsequent loading to the PVA brush nodule. Higher cleaning of particles from wafer was observed for pH 2 and 12 cleaning solutions and poor cleaning for pH 7 cleaning solution. In contrast, the brushes were loaded heavily for pH 7 compared to pH 2 and 12. Higher electrostatic attraction between oppositely charged PVA and ceria surfaces provided higher ceria particles loading to PVA brush in acidic and neutral cleaning solutions. This particle loading to PVA brush can further effect cleaning efficiency as well as cross-contamination.

Abstract: Investigations of microarc calcium phosphate (CaP) boehmite-containing biocoatings on the pure titanium (Ti) alloy were presented. There were discovered relationships of coating properties (morphology, elemental and phase composition, zeta-potential, wettability) on the boehmite deposition parameters. A variation of the modification parameters of boehmite nanoparticles deposition allowed producing hydrophilic boehmite-containing CaP coatings with the roughness of 2.2-3.1 μm and nanoscale morphology. The influence of boehmite nanoparticles on the surface zeta-potential of the coating was found.

Abstract: The interaction of spray-based physical clean and hydrophobic surfaces is studied on a single-wafer technology. A model simulating a rolling water marble on a rotating disk describes accurately the footprint of watermarks, Contrary to its oxide, on a silicon surface the adhesion of particles does not depend on the pH value but on the rotation speed. This newly proposed method, based on the simultaneous combination of spray and liquid dispense is then compared to the standard IPA-based process. Despite the non-usage of solvents, the substrates show similar particles level, defectivity and epi-growth quality.

Abstract: Method of electric-spark dispersion of iron particles in water, ethyl alcohol, phosphoric acid solution and hexane has been applied to produce composite magnetic nanosized powders. Their phase composition, dispersity, magnetic susceptibility, and adsorption-desorption properties towards anti-tumor remedy doxorubicin have been studied. It is shown that the obtained powder in hexane has the highest adsorption capacity towards doxorubicin. This is probably the evidence of surface compound formation. It is durable adsorption complex, which is formed from carbonyl and amine groups of organic cations and vacant orbitals of iron d-sublevel. The powder, obtained in hexane, can be dissolved in human blood plasma and amino acid solutions: possible time of iron elimination from human organism is smaller than 10 days. It is shown possibility of application iron-carbon sorbent is in quality of magnetic carrier doxorubicin to cancer cells.

Abstract: The contribution of microorganisms, particularly bacteria, in carbonate mineral formation, the main natural processes controlling CO₂ level in the atmosphere, has played an important role since the Archean Eon. In this study we review our recent experimental work on CaCO₃ precipitation induced by two anoxygenic phototrophic bacteria (APB), Rhodovulum steppense A-20s^T and Rhodovulum sp. S-17-65, and by cyanobacteria Gloeocapsa sp. f-6gl. These bacteria are representatives of two important groups of photosynthetic organisms present at the Earth surface both in the past and at the present times. The mechanisms of organomineralization deriving from APB and cyanobacteria activities are drastically different and relate to the main physical and chemical processes controlling CaCO₃ precipitation from aqueous solution, essentially local supersaturation with respect to carbonates induced by photosynthesis outside the living cells and Ca adsorption onto cell surface and the associated extracellular polymeric substances (EPS).The APB can physiologically control their surface potential to electrostatically attract nutrients at alkaline pH, while rejecting Ca ions to prevent Ca adsorption and subsequent CaCO₃ precipitation in the vicinity of cell surface and thus, cell incrustation. In contrast to other previously-investigated calcifying bacteria, no cellular protection mechanism against Ca²⁺ adsorption and subsequent carbonate precipitation has been evidenced for cyanobacteria Gloeocapsa sp. f-6gl. This is most likely linked to the peculiar cellular organization of this species that involves several cells clustered in one single capsule. In this regard, colony-forming, EPS-rich, capsular cyanobacteria may be among the most efficient calcifying microorganisms all along the Earth history and can be of interest for various technological applications involving carbonation.

Abstract: The surfaces of three China coals varying widely in coal type(Baode,Xiangshan,Jincheng) have been modified by adsorption of three surfactants( Sodium dodecyl sulfate,Polyethoxylated fatty alcohols,Alkyl phenol gather oxygen vinyl ether).The impact about coals of the surfactant has been explored by correlating three chemical characterisation techniques.Changes in coal surface hydrophobicity were assessed using contact angle measurements at the coal/water interface.The largest variation in zeta potential resulting from addition of surfactants was seen for the higher rank coals.The Specific surface area decreased when surfactants were present.

Abstract: Based on the profound application, the Co₃O₄ was chosen to be research object; the optimized dispersing condition was studied and determined as: dosage of Co₃O₄ nano particle varied from 0.01 to 0.02mg/ml, sodium citrate was determined to be dispersing adjuvant with a dosage of 0.0005g/ml, ultrasonic time: 10min, and pH value was 7 to 8 when the Zeta potential was –57.1mv. After a detailed discussion of size distribution and dispersing condition, the size distribution of Co₃O₄ nano particle was measured with Malvern Nano Zetasizer to be 217nm.

Abstract: A lower salt resistance sulfomethylated phenol formaldehyde resin (LSMP) was synthesized. The dispersion properties of LSMP and influences of reaction conditions on its properties were investigated with dynamic light scattering technology, and means of viscosity and critical coagulating concentration (CCC) determination. The result shows that the viscosity of a 1.0 g•L-1 resin solution ranges from 0.8036 mPaּs to 0.8705 mPaּs, and unit in distilled water exhibits a hydrodynamic diameter between 8.5 nm and 123.4 nm and a Zeta potential varying from -76.05 to -21.12 mV under different reaction conditions. The dispersing system of LSMP in water is a kind of colloid solution and electrolytes can weaken the resin dispersion and make the resin flocculate, and the solution of LSMP in water is hypersensitive to positive ions and effects of positive ions will be more obvious with increasing valence of ions.

Abstract: Concrete admixture has become one of essential components of the high performance concrete in recent years; however, the quality of high performance concrete fluctuates according to the compatibility between cement and admixture it used. Considering lower alkali cement is often provided by cement producers in order to get better durability of concrete, so low alkali cement and naphthalene-based superplasticizer were used as the main test materials in this paper. The causes of the compatibility between low alkali cement and superplasticizer were studied, and then several measures were proposed to improve the compatibility.

Abstract: A zwitterionic copolymer has been synthesized and a common optimum concentration of dispersant for the stabilized Al₂O₃ suspensions is found at 0.04wt%, which represents the adsorption saturation limit of polyelectrolytes at Al₂O₃ –water interface at pH = 10. Based on the results from rheological measurements, involving the effect of dispersant concentration, a stable broader dispersant concentration range of 0.4wt% ~ 0.22wt% is observed for suspensions with solids loading ≤ 50vol%, a stable broader pH range of 7.0 ~ 11.2 for suspension with solids loading ≤ 50vol%, and a stable pH range of 1.2 ~ 2.0 for suspensions with solids loading ≤ 40vol%.