scholarly journals Study on Functionality and Surface Modification of a Stair-Step Liquid-Triggered Valve for On-Chip Flow Control

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 690
Author(s):  
Xi Chen ◽  
Sihui Chen ◽  
Yi Zhang ◽  
Hui Yang
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Microfluidic System ◽  
Chip Flow ◽  
Initial Stage ◽  
Surface Contact ◽  
Surface Contact Angle ◽  
Fluidic Control ◽  
On Chip ◽  
Micro Systems

Distinctive from other forms of microfluidic system, capillary microfluidics is of great interest in autonomous micro-systems due to its well-engineered fluidic control based on capillary force. As an essential component of fluidic control in capillaric circuits, micro-valves enable sequential fluidic operations by performing actions such as stopping and triggering. In this paper, we present a stair-step liquid-triggered valve; the functionality of the valve and its dependencies on geometry and surface modification are studied. The surface contact angle of the microfabricated valves that are coated by polyethylene glycol (PEG) or (3-Aminopropyl) triethoxysilane (APTES) is evaluated experimentally, and the corresponding reliability of the valve structure is discussed. Moreover, the variation in the surface contact angle over time is investigated, indicating the shelf time of the device. We further discuss the overall fluidic behavior in such capillary valves, which benefits the capillaric circuit designs at the initial stage.

scholarly journals Photocatalytic Surface Modification of PI Film for Electroless Copper Plating

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Wenxia Zhao ◽  
Zenglin Wang ◽  
Liang Qiao ◽  
Shiwei Liu ◽  
Hongjian Zhao ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Adhesion Strength ◽  
Photoelectron Spectroscopy ◽  
Carboxyl Groups ◽  
Electroless Copper Plating ◽  
Electroless Copper ◽  
Surface Contact ◽  
Surface Contact Angle ◽  
Surface Modified

This study investigated the surface modification of polyimide (PI) film through TiO2 photocatalytic treatment. The effects of TiO2 content, treatment duration, and UV power on the surface topography, surface contact angle, and adhesion strength of the surface-modified PI films were investigated. The results indicated that, after surface modification under the optimal photocatalytic conditions, the surface contact angle of the PI film decreased from 84.4° to 38.8°, and the adhesion strength between the PI film and the electroless copper film reached 0.78 kN/m. X-ray photoelectron spectroscopy analysis further demonstrated that carboxyl groups formed on the surface of the PI film after photocatalytic treatment. The surface hydrophilicity and adhesion strength of the surface-modified PI film were enhanced due to the numerous carboxyl groups formed on its surface. Therefore, the photocatalytic treatment is an environmentally friendly and effective method for the surface modification of PI films.

scholarly journals Surface Tracking of MgO/Epoxy Nanocomposites: Effect of Surface Hydrophobicity

2019 ◽  
Vol 9 (3) ◽  
pp. 413 ◽  
Author(s):  
Zhaoliang Xing ◽  
Chong Zhang ◽  
Xiangnan Hu ◽  
Panhui Guo ◽  
Jingyuan Zhang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Electric Fields ◽  
Surface Hydrophobicity ◽  
Surface Charges ◽  
Surface Tracking ◽  
Surface Contact ◽  
Surface Contact Angle ◽  
Tracking Behavior ◽  
Composite Samples ◽  
Reduced Surface

Surface tracking has been one of the challenges for outdoor organic insulations, in electronic and electrical devices. In this paper, surface tracking behavior of nano-MgO/epoxy composite samples were measured according to the standard IEC 60112. Improved tracking resistance was obtained in nanocomposites with an 18.75% uplift in the comparative tracking index, and a decrease of 58.20% in the surface ablation area at a fixed 425 V. It was observed that the tracking resistance and surface hydrophobicity shared the same tendency—both, the comparative tracking index and surface contact angle increased with an increase of the nanofiller content. Samples with better hydrophobicity exhibited a higher tracking resistance. It could be the case that the conductive pathway of contamination was harder to form, as a result there were fewer discharging processes. With the development of surface tracking, the surface contact angle abruptly decreased, at first, and tended to be constant, which was also accomplished with the failure of samples. In addition, reduced surface resistivity was also found in the nanocomposites, which was beneficial for releasing surface charges and inhibiting distortions in the electric fields.

DEVELOPMENT OF CARBON-BASED COATING OF EXTREMELY HIGH TOUGHNESS WITH GOOD HARDNESS

2004 ◽  
Vol 03 (04n05) ◽  
pp. 571-578 ◽  
Author(s):  
S. ZHANG ◽  
X. L. BUI ◽  
Y. FU ◽  
H. DU
Keyword(s):  
Residual Stress ◽  
Contact Angle ◽  
Amorphous Carbon ◽  
High Hardness ◽  
Hydrophobic Surface ◽  
Nanocomposite Coating ◽  
High Toughness ◽  
Surface Contact ◽  
Surface Contact Angle ◽  
Carbon Based

Metallic Al was doped into amorphous carbon (a-C) to form a matrix of a-C(Al) of very low residual stress and high toughness at the expense of some hardness. Nanocrystallites of TiC (nc-TiC) of a few nanometers in size were embedded in this matrix to bring back the hardness. The nanocomposite coating of nc-TiC/a-C(Al) was deposited via co-sputtering of graphite, Ti , and Al targets. Although the nanocomposite coating exhibited a moderately high hardness (about 20 GPa), it possessed extremely high toughness (about 55% of plasticity during indentation deformation) and low residual stress (less than 0.4 GPa), smooth (Ra=5.5 nm ), and hydrophobic surface (contact angle with water reaches 100°).

scholarly journals Comparative Study on Wettability of Typical Plant Leaves and Biomimetic Preparation of Superhydrophobic Surface of Aluminum Alloy

2018 ◽  
Vol 142 ◽  
pp. 04004 ◽  
Author(s):  
Yanhong Sun ◽  
Xinxin Gao ◽  
Jinnong Li ◽  
Ying Chen
Keyword(s):  
Contact Angle ◽  
Aluminum Alloy ◽  
Comparative Study ◽  
Superhydrophobic Surface ◽  
Theoretical Research ◽  
Plant Leaves ◽  
Hydrophobic Property ◽  
Direction Parallel ◽  
Surface Contact ◽  
Surface Contact Angle

The water droplets spread observation, contact angle measurement and SEM analysis, data processing and other means, comparative study of different states of the lotus leaf, rice leaf and nasturtium leaf are carried out. The results show that their surface contact angle of three kinds of plant leaves are all over 140°, they have hydrophobic or superhydrophobic properties; dehydration degree of leaves has little effect on the wettability, will not change its hydrophobic property; the same point of wettability is that they have micro nano composite microstructure. The difference is, the wettability of the lotus and nasturtium is isotropic, while the rice is anisotropic, that is, in a direction parallel to the edge of hydrophobic than perpendicular to the blade edge enhancement. Based on the theoretical research, the hydrophobic surface is copied to the surface of aluminum alloy. The superhydrophobic surface of aluminum alloy matrix was successfully prepared by chemical etching combined with surface fluorination. The super hydrophobic aluminum alloy surface has micron-nano scale double roughness structure; its surface contact angle reached 156°.

scholarly journals Large area optical mapping of surface contact angle

2017 ◽  
Vol 25 (18) ◽  
pp. 21127 ◽  
Author(s):  
Guilherme Dutra ◽  
John Canning ◽  
Whayne Padden ◽  
Cicero Martelli ◽  
Svetlana Dligatch
Keyword(s):  
Contact Angle ◽  
Optical Mapping ◽  
Large Area ◽  
Surface Contact ◽  
Surface Contact Angle

Protein engineering of a new recombinant peptide to increase the surface contact angle of stainless steel

RSC Advances ◽  
2015 ◽  
Vol 5 (123) ◽  
pp. 101309-101318 ◽  
Author(s):  
X. Y. Ren ◽  
X. Q. Bai ◽  
C. Q. Yuan ◽  
Y. Yang ◽  
H. Xie ◽  
...  
Keyword(s):  
Contact Angle ◽  
Stainless Steel ◽  
Service Life ◽  
Protein Engineering ◽  
Recombinant Peptide ◽  
Surface Contact ◽  
Surface Contact Angle ◽  
Metal Materials

Biofouling seriously affects the properties and service life of metal materials.

An Integrated Microfluidic Device for the Continuous Sampling and Analysis of Biological Fluids

2001 ◽  
Author(s):  
Jeffrey D. Zahn ◽  
Ajay A. Deshmukh ◽  
Alexandros P. Papavasiliou ◽  
Albert P. Pisano ◽  
Dorian Liepmann
Keyword(s):  
Molecular Weight ◽  
Chemical Sensor ◽  
Biological Fluids ◽  
Microfluidic System ◽  
Integrated Sensor ◽  
Continuous Sampling ◽  
Positive Displacement ◽  
Chip Flow ◽  
Large Molecular Weight ◽  
On Chip

Abstract Enzyme based biosensors suffer from loss of activity and sensitivity. One major reason is due to large molecular weight proteins adsorbing on the surface of the sensor. These proteins affect sensor signal stability and disrupt enzyme function. Thus, one fruitful way to minimize the loss of sensor activity is to filter out large molecular weight compounds before they come in contact with the enzyme based biosensor. Further, the removal of free protein from biological solution helps to increase sensor accuracy and lifetime. Therefore, a microdialysis microneedle is introduced that is capable of excluding large MW compounds based on size. These microneedles have been integrated into a planar microfluidic system capable of sampling and analyzing biological solutions. The integrated microfluidic system includes the assembly of microneedles with on-chip flow channels and electronics together with previously designed positive displacement micropumps, microvalves and a planar electro-chemical sensor for biological detection. Multichannel fluidic control for biological sampling, sensor cleansing and recalibration is demonstrated with integrated sensor operation.

Droplet Compression and Relaxation by a Superhydrophobic Surface: Contact Angle Hysteresis

Langmuir ◽  
2012 ◽  
Vol 28 (13) ◽  
pp. 5606-5613 ◽  
Author(s):  
Siang-Jie Hong ◽  
Tung-He Chou ◽  
Seong Heng Chan ◽  
Yu-Jane Sheng ◽  
Heng-Kwong Tsao
Keyword(s):  
Contact Angle ◽  
Superhydrophobic Surface ◽  
Contact Angle Hysteresis ◽  
Surface Contact ◽  
Surface Contact Angle

scholarly journals Study on Influence of Surface Plasma Activation of Quartz Fiber/Cyanate Ester Composite at Meter Range Working Distance

2022 ◽  
Vol 2160 (1) ◽  
pp. 012028
Author(s):  
Chao Meng ◽  
Shoujing Yue ◽  
Lixin Xuan ◽  
Zhandong Ma ◽  
Jigang Wang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Plasma Treatment ◽  
Bonding Strength ◽  
Bending Strength ◽  
Cyanate Ester ◽  
Quartz Fiber ◽  
Activation Effect ◽  
Surface Contact ◽  
Surface Contact Angle ◽  
Working Distance

Abstract The surface of quartz fiber/cyanate ester composite at meter working distance was activated by plasma treatment technology. Influence of plasma treatment parameters on surface contact angle of the composite was investigated, as well as changes of surface morphology, intrinsic performance and membrane-based bonding strength. Results showed that surface contact angle of the composite decreased significantly after plasma treatment with nitrogen and argon. Moreover, activation effect of argon plasma was better than that of nitrogen plasma. With the increase of voltage, surface contact angle of composite became smaller and activation effect was better. After plasma treatment, glass transition temperature (Tg) and bending strength of the composite did not change, and intrinsic property of the composite was not damaged. After plasma treatment, surface roughness and specific surface area of the composite increased, and membrane-based bonding strength of the composite with Al coating increased significantly.

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