scholarly journals Surface Organic Modification of TiO2 Powder and Relevant Characterization

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Hong Zhou ◽  
Sijia Sun ◽  
Hao Ding
Keyword(s):  
Contact Angle ◽  
Sodium Oleate ◽  
Particle Surface ◽  
Sodium Stearate ◽  
Surface Characteristics ◽  
Organic Modification ◽  
Modification System ◽  
Wetting Contact Angle ◽  
Inorganic Medium ◽  
Before And After

Surface organic modification was conducted to TiO2 with modifiers to improve the dispersity and comparability of pigment TiO2 in application system by adjusting particle surface characteristics. Then, modification effects were characterized according to the changes in wetting contact angle and activation index of TiO2 before and after modification. Moreover, the modification mechanisms of sodium stearate and sodium oleate were studied by analyzing the characteristics of TiO2 surface functional groups in modification system and effects of modifiers. The results showed that, after being wet-processed with sodium stearate and sodium oleate, TiO2 could turn from surface hydrophilic to inductive hydrophobic with controllable degree. The wetting contact angle of modified TiO2 increased from 7° to 125.6° and 121.3°, respectively. The dispersity of TiO2 in organic medium was stronger than that in inorganic medium. The modifiers formed absorption with chemical property on TiO2 particle surface, so the inductive hydrophobicity of surface was stable.

Surface Roughness and Droplet Contact Angle Measurement of Various Orthodontic Bonding Cements

1993 ◽  
Vol 20 (4) ◽  
pp. 297-305 ◽  
Author(s):  
C. O'Kane ◽  
R. G. Oliver ◽  
R. E. Blunden
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Glass Ionomer Cement ◽  
Surface Characteristics ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Bacterial Attachment ◽  
Before And After ◽  
Orthodontic Bonding

Surface characteristics that are considered important for bacterial attachment to thirteen orthodontic bonding composite cements and one glass ionomer cement were examined in vitro before and after toothbrush abrasion. The surface roughness and contact angle measurements were found to be statistically significantly different between the materials, both before and after brushing, and there were also statistically significant changes within materials after brushing. There were low correlation coefficients between surface roughness and contact angle for both pre-and post-brushed materials.

Particle surface characteristics of permanently charged poly(styrene-cationic comonomer) latices

1990 ◽  
Vol 26 (1) ◽  
pp. 35-39 ◽  
Author(s):  
W.M. Brouwer ◽  
M. van der Vegt ◽  
P. van Haeren
Keyword(s):  
Particle Surface ◽  
Surface Characteristics

Performance Impacts of Tailored Surface Geometry in Li-Ion Battery Cathodes

2013 ◽  
Author(s):  
George J. Nelson
Keyword(s):  
Surface Area ◽  
Solid Phase ◽  
Particle Surface ◽  
Surface Characteristics ◽  
Analytical Models ◽  
Li Ion Battery ◽  
Fractal Structures ◽  
Surface Geometry ◽  
Trade Offs ◽  
Li Ion

Analytical models developed to investigate charge transfer in Li-ion battery cathodes reveal distinct transport regimes where performance may be limited by either microstructural surface characteristics or solid phase geometry. For several cathode materials, particularly those employing conductive additives, surface characteristics are expected to drive these performance limitations. For such electrodes gains in performance may be achieved by modifying surface geometry to increase surface area. However, added surface area may present a diminishing return if complex structures restrict access to electrochemically active interfaces. A series of parametric studies has been performed to better ascertain the merits of complex, tailored surfaces in Li-ion battery cathodes. The interaction between lithium transport and surface geometry is explored using a finite element model in which complex surfaces are simulated with fractal structures. Analysis of transport in these controlled structures permits assessment of scaling behavior related to surface complexity and provides insight into trade-offs in tailoring particle surface geometry.

scholarly journals FIELD MEASUREMENTS ON RUNWAY FRICTION DECAY RELATED TO RUBBER DEPOSITS

Transport ◽  
2016 ◽  
Vol 31 (2) ◽  
pp. 177-182 ◽  
Author(s):  
Mario De Luca ◽  
Francesco Abbondati ◽  
Thomas J. Yager ◽  
Gianluca Dell’Acqua
Keyword(s):  
Functional Capacity ◽  
Field Measurements ◽  
Surface Characteristics ◽  
Air Traffic ◽  
Pavement Surface ◽  
Vulcanized Rubber ◽  
Before And After

Surfaces of airport pavements are subject to contamination that can be very dangerous for the movement of aircraft particularly on the runway. A recurrent problem is represented by the deposits of vulcanized rubber of aircraft tires in the touchdown area during landings and lesser during take-offs. This causes a loss of grip that compromises the safety of aircraft movements in take-off and landing operations. This study deals with the surface characteristics decay phenomenon related to contamination from rubber deposits. The experiment was conducted by correlating the pavement surface characteristics, as detected by Grip Tester, to air traffic before and after de-rubberizing operation and two models were constructed for the assessment of functional capacity of the runway before and after the operations de-rubberizing.

scholarly journals Effects of Anti-Graffiti Protection on Concrete Durability

2014 ◽  
Vol 634 ◽  
pp. 517-526 ◽  
Author(s):  
Elsa Neto ◽  
Ana Souto ◽  
Aires Camões ◽  
Arlindo Begonha ◽  
Paulo Cachim
Keyword(s):  
Water Absorption ◽  
Atmospheric Pressure ◽  
Surface Characteristics ◽  
Concrete Surface ◽  
Experimental Program ◽  
Concrete Durability ◽  
Protection Systems ◽  
Before And After ◽  
Paint Removal ◽  
Durability Of Concrete

The heritage of fair-faced concrete, largely built in the twentieth century and nowadays recognized as heritage to be protected, is susceptible to attacks by graffiti, a form of vandalism that causes a major social and economic impact on society. Concrete is a porous material sometimes deteriorated over the years, and the interactions between the inks and the substrate and removal methods sometimes deteriorate or alter the concrete surface, especially if it is necessary to repeat the removal process. The anti-graffiti products are applied on the surface of the concrete, hindering the adhesion of paints or preventing its penetration into the pores of concrete, which in turn facilitates their removal. However, it appears that many of the existing protective products on the market may also alter the surface characteristics of the concrete irreversibly. Considering that the durability of concrete depends on the composition and characteristics of the surface, it is essential to know the effects of anti-graffiti protection systems on the durability of concrete and adopt the appropriate methodology to preserve this heritage. Thus, an experimental program was developed for analyzing changes in durability indicators and surface properties that protect concrete from deterioration (i) concrete without protection before and after application of spray paint, (ii) concrete with protection before and after application of spray paint and (iii) after paint removal were studied. Two anti-graffiti products were evaluated: a permanent and a sacrificial one. Effects of the anti-graffiti systems on the concrete durability are investigated and the tests performed include: water absorption by capillary and immersion at atmospheric pressure. The results of the water absorption tests show that the graffiti protection reduces the water absorption into the concrete and facilitates the removal of the graffiti without affecting negatively the characteristics of the surface and thus contributing to improve its durability.

Curing Time and Water Repellent Properties of Dammar-Titanium Dioxide Thin Film

2015 ◽  
Vol 1112 ◽  
pp. 359-362
Author(s):  
Aisyah Nor Hasnan ◽  
Azizah Hanom Ahmad
Keyword(s):  
Contact Angle ◽  
Titanium Dioxide ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Water Repellent ◽  
Coating System ◽  
Curing Time ◽  
Coating Surface ◽  
Natural Resin ◽  
Before And After

Dammar plant resin is a local natural resin that can be bled from Dipterocaupacea sp of tree. It can be found abundantly in Malaysia’s tropical forest especially in Sarawak. Dammar and Titanium Dioxide was mixed in a various wt% to produce Dammar-modified Titanium Dioxide coating system. The modified coating systems were then spin-coated onto Aluminium Q-panel as the substrate. Coated Q-panels were left to cure at room temperature. The curing time was evaluated using dust free stage. The addition of Titanium Dioxide into the coating system fastens the curing time taken for the coated Q-panel to be cure. It only took about 11-12 minutes to dry compared to the coating system before the addition of Titanium Dioxide where a quite long duration required, 32 minutes. Contact angle measurement was also carried out in order to determine the wettability of the coating system. The surface coated with dammar-modified titanium dioxide found to be hydrophobic where a quite large contact angle obtained for the sample with 3 wt% of Titanium Dioxide (PDT3). The water droplets actually rest on the coating surface without wetting the surface. Water absorption test was done to strengthen the contact angle results where coated substrate was soaked into distilled water for 24 hours and being weighed before and after soaking. The difference of before and after soaking weigh showed that the coating surface does not absorb that much water where only approximately 0.02% of water being absorbed by the coating system for 3 wt%. It proved that the coating systems applied are hydrophobic.

Additive Adsorption and Interfacial Characteristics of Nucleate Pool Boiling in Aqueous Surfactant Solutions

2005 ◽  
Vol 127 (7) ◽  
pp. 684-691 ◽  
Author(s):  
Juntao Zhang ◽  
Raj M. Manglik
Keyword(s):  
Contact Angle ◽  
Pure Water ◽  
Pool Boiling ◽  
Dynamic Surface Tension ◽  
Nucleate Pool Boiling ◽  
Dynamic Surface ◽  
Wetting Contact Angle ◽  
Optimum Heat ◽  
Adsorption Desorption ◽  
And Control

Interfacial phenomena and ebullient dynamics in saturated nucleate pool boiling of aqueous solutions of three surfactants that have different molecular weight and ionic nature are experimentally investigated. The additive molecular mobility at interfaces manifests in a dynamic surface tension behavior (surfactant adsorption–desorption at the liquid–vapor interface), and varying surface wetting (contact angle) with concentration (surfactant physisorption at the solid–liquid interface). This tends to change, enhance, and control the boiling behavior significantly, and an optimum heat transfer enhancement is obtained in solutions at or near the critical micelle concentration (CMC) of the surfactant. Furthermore, wettability (contact angle) is observed to be a function of the molecular makeup of the reagent, and shows distinct regions of change along the adsorption isotherm that are associated with the aggregation mode of adsorbed ions at the solid–water interface. This distinguishably alters the ebullience from not only that in pure water, but also between pre- and post-CMC solutions. Increased wetting tends to suppress nucleation and bubble growth, thereby weakening the boiling process.

Effect of Quartz Sand Coated with Water-Treatment Residuals as Arsenic Adsorbent

2013 ◽  
Vol 663 ◽  
pp. 1064-1069 ◽  
Author(s):  
Chi Chuan Kan ◽  
Meng Wei Wan ◽  
Hui Ling Yang ◽  
Chih Chao Wu
Keyword(s):  
Water Treatment ◽  
Quartz Sand ◽  
Arsenic Concentration ◽  
Surface Characteristics ◽  
Isotherm Models ◽  
Water Treatment Residuals ◽  
Arsenic Adsorption ◽  
Average Pore ◽  
Before And After ◽  
Iron Manganese

In this study, quartz sand coated with water-treatment residuals was tested for its effectiveness as an arsenic adsorbent. The surface characteristics of the quartz sand before and after modification were analyzed. Different amounts of modified quartz sand were then tested for their adsorption capacity, using raw water with an arsenic concentration of 500 ppb. Analysis showed that the surface area and average pore diameter of the quartz sand had increased significantly after modification, as did the amounts of iron, manganese, and aluminum found as surface elements. Using both Freundlich and Langmuir isotherm models to measure the effectiveness of arsenic adsorption by the modified quartz sand, it was found that the latter model, for monolayer adsorption, was more appropriate.

The effect of surfactant concentration on nanoparticles surface wettability during wettability alteration of oil-wet carbonate rock

2021 ◽  
Vol 15 (2) ◽  
pp. 7993-8002
Author(s):  
Wan Mohd Shaharizuan Mat Latif ◽  
M. S. M. Musa ◽  
A.S.M. Balakirisnan ◽  
W. R. W. Sulaiman
Keyword(s):  
Contact Angle ◽  
Silicon Dioxide ◽  
Carbonate Rock ◽  
Surfactant Concentration ◽  
Sodium Dodecyl ◽  
Particle Surface ◽  
Surface Wettability ◽  
Wettability Alteration ◽  
Inverse Effect ◽  
Sds Surfactant

Previous studies reported that the presence of surfactant increases nanoparticles surface wettability by in-situ surface activation. On the other hand, the excess of surfactant concentration has an inverse effect on particle hydrophobicity by altering it to be hydrophilic back. Hence, this study presents an experimental investigation of wettability alteration by using a surfactant-nanoparticles system by using cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) surfactant, and hydrophilic silicon dioxide (SiO2) and partially hydrophobic silicon dioxide (PH SiO2) nanoparticles. The nanoparticles surface wettability and the wettability alteration of oil-wet carbonate rock were measured by using the contact angle method. The result shows that the contact angle of the oil-wet carbonate rock was most reduced by using CTAB-hydrophilic SiO2, from 112.00o to 28.35o. The excess of surfactant concentration (beyond CMC) shows an inverse effect on particle surface wettability, however, induces the water-wetness of the carbonate rock. Besides, the hydrophilic SiO2 shows a more effective effect as a wettability modifier than the PH SiO2, in the absence and presence of CTAB or SDS surfactant.

Sign in / Sign up

Export Citation Format

Share Document