scholarly journals Noncovalent Spiropyran Coatings for Photoinduced Wettability Switching

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Matthias Bremer ◽  
Ruprecht Reinke ◽  
Britta Hesseler ◽  
Mohammadreza Taale ◽  
Daniela Ingwersen ◽  
...  
Keyword(s):  
Contact Angle ◽  
Uv Light ◽  
Green Light ◽  
Casting Process ◽  
Initial Contact ◽  
Initial Contact Angle ◽  
Candle Soot ◽  
Angle Difference ◽  
Coating Procedure ◽  
Microscopy Images

The noncovalent binding of spiropyran to candle-soot-covered surfaces is investigated for wettability switching using a coating procedure realized with a drop casting process of using 0.001 mol/L spiropyran in a 5 : 1 toluene-acetone mixture. Scanning electron microscopy images reveal a resulting surface with spiropyran flakes in the candle soot. A reversible switching with UV light and blue or green light is achieved, starting from an initial contact angle of 130°  ± 9.68°. The highest contact angle difference is 41° and reversibility has been shown for several switching cycles. Hence, our methods provide an easy-to-use strategy to generate surfaces with switchable wettability.

Initial Contact Angle of the Foot Segment and GRF Components by the Gender Differences

2018 ◽  
Vol 57 (2) ◽  
pp. 625-633
Author(s):  
Sangheon Park ◽  
Sukhoon Yoon ◽  
Sang-Kyoon Park ◽  
Jiseon Ryu
Keyword(s):  
Gender Differences ◽  
Contact Angle ◽  
Initial Contact ◽  
Initial Contact Angle

scholarly journals Effect of Glow-Discharge Plasma Treatment on Contact Angle and Micromorphology of Bamboo Green Surface

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1293
Author(s):  
Xuehua Wang ◽  
Kenneth J. Cheng
Keyword(s):  
Electron Microscopy ◽  
Contact Angle ◽  
Glow Discharge ◽  
Plasma Treatment ◽  
Discharge Plasma ◽  
Glow Discharge Plasma ◽  
Initial Contact ◽  
Initial Contact Angle ◽  
Utilization Ratio ◽  
Scanning Electron

The inner and outer surfaces of bamboo stems are usually removed prior to the manufacture of bamboo panels because the surfaces are hydrophobic and difficult to bond with glue. Hence, the recovery and utilization ratio of bamboo during processing is low. This study focused on using glow-discharge plasma to treat green bamboo surfaces to make them less hydrophobic. The effects of plasma treatment on green bamboo stems were examined using contact goniometry (wettability), non-contact confocal profilometry and scanning electron microscopy (SEM). Confocal profilometry and SEM revealed that the morphology of green bamboo surfaces varied between 3 different stems. Plasma was able to etch bamboo green surfaces, and make them rougher and more powdery. Plasma treatment was effective at converting green bamboo surfaces from hydrophobic (initial contact angle >110°) to hydrophilic (contact angle <20°). However, this effect was temporary and contact angle increased with time and recovered approximately 30% of its original value after 24 h. Based on our findings, we conclude that plasma treatment can alter parameters such as surface energy and roughness that could improve glue bonding of green bamboo, but delays between plasma treatment and further processing would need to be minimized.

Dependence of the structure of ring-shaped deposits resulting from evaporation of dispersion droplets on initial contact angle

2016 ◽  
Vol 78 (5) ◽  
pp. 633-640 ◽  
Author(s):  
S. P. Molchanov ◽  
V. I. Roldughin ◽  
I. A. Chernova-Kharaeva ◽  
G. A. Yurasik
Keyword(s):  
Contact Angle ◽  
Initial Contact ◽  
Initial Contact Angle

Controlling the contact angle of biological sessile drops for study of their desiccated cracking patterns

2018 ◽  
Vol 6 (37) ◽  
pp. 5867-5875 ◽  
Author(s):  
Ruoyang Chen ◽  
Liyuan Zhang ◽  
Wei Shen
Keyword(s):  
Contact Angle ◽  
Initial Contact ◽  
Initial Contact Angle ◽  
Sessile Drops

Controlling the initial contact angle of biological sessile drops to advance the study and applications of their desiccated cracking patterns.

Investigation of Optimizing Arrangement Forms for Combined Angular Contact Ball Bearings

2017 ◽  
Author(s):  
Bin Fang ◽  
Jinhua Zhang ◽  
Jun Hong ◽  
Yongsheng Zhu ◽  
Xu Wang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Contact Angle ◽  
Load Distribution ◽  
Contact Angles ◽  
Rotating Machinery ◽  
Initial Contact ◽  
Ball Bearings ◽  
Heavy Load ◽  
Initial Contact Angle ◽  
Machinery System

The combined angular contact bearings are widely used in numerous rotating machinery system, but few research works on the combined angular contact ball bearings have been reported. To solve the problem about inconsistency fatigue life of the bearings in the combined bearings with asymmetric arrangement, this paper proposed a special combined bearings arrangement form in which the bearings with different contact angles are used simultaneously for the bearing combination. In order to validate the effectiveness of the proposed method, a mathematical model is proposed to analyze the load distribution, life and stiffness of the combined bearings, and the combined bearings with three different arrangements are comparatively calculated and analyzed. The results show that the whole life of combined bearings is mainly depend on the life of the bearing under heavy load, and the new arrangement form in which the initial contact angle of the bearing under heavy load is increased that can improve the whole life of combined bearings.

Research On Non-boiling Evaporation Behavior of Fixed Droplets On Aluminum Plate Surface

2021 ◽  
Author(s):  
Liansheng Liu ◽  
Xuanchen Liu ◽  
Wenjia Ren ◽  
Hongbin Duan ◽  
Runze Duan ◽  
...  
Keyword(s):  
Contact Angle ◽  
Evaporation Rate ◽  
Aluminum Plate ◽  
Initial Contact ◽  
Plate Surface ◽  
Evaporation Time ◽  
Plate Temperature ◽  
Initial Contact Angle ◽  
Initial Volume ◽  
Contact Diameter

Abstract In this paper, the non-boiling evaporation (30 -70?) of the fixed droplets on the Aluminum plate surface was investigated by the experiment. The effect of the plate temperature and initial volume on the contact angle, contact diameter and evaporation time were considered. The results showed that the temperature and initial volume were important for the droplets evaporation. As the heating plate temperature increased, the evaporation rate increased and the initial contact angle decreased. At the same heating plate temperature, the evaporation rate and the initial contact angle decreased with the increase of the droplets initial volume. At the constant temperature hydrophilic surface, the droplet evaporation is performed in two modes: Constant contact radius mode (CCR mode) and mix mode. The CCR mode were about 90% of the time at the droplets evaporation process and the droplet contact diameters kept constant with the increase of the evaporation time. For the mix mode, the contact angle and contact diameter decreased with the increase of the evaporation time.

New Results on Electroluminescence from Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
Peter Steiner ◽  
Frank Kozlowski ◽  
Hermann Sandmaier ◽  
Walter Lang
Keyword(s):  
Porous Silicon ◽  
Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Green Light ◽  
Light Emitting ◽  
Porous Region ◽  
First Results

ABSTRACTFirst results on light emitting diodes in porous silicon were reported in 1991. They showed a quantum efficiency of 10-7 to 10-5 and an orange spectrum. Over the last year some progress was achieved:- By applying UV-light during the etching blue and green light emitting diodes in porous silicon are fabricated.- When a p/n junction is realized within the porous region, a quantum efficiency of 10-4 is obtained.

Enhancing the Strengths of Adhesion Bonds Between Composite Surface and Coating via UV Treatments

2017 ◽  
Author(s):  
R. Asmatulu ◽  
K. S. Erukala ◽  
M. M. Rahman
Keyword(s):  
Contact Angle ◽  
Uv Radiation ◽  
Uv Light ◽  
Composite Coatings ◽  
Weight Ratio ◽  
High Strength ◽  
Water Contact ◽  
Composite Surface ◽  
Adhesion Properties ◽  
Infrared Spectrometer

Field of composites is rapidly growing in many industries such as aviation, energy and automotive industries. Composites are known to have a high strength to low weight ratio. Significant improvement in the performance of coatings used in the protection of military and civil aircraft has been achieved the last thirty years. Composite coatings are exposed to many environmental conditions, which can significantly affect their properties. In this research, UV light treatment on the surface of composite was introduced to examine its effects on the adhesion properties between the coating and substrate. A cross-cut test was conducted on the composite panels to assess the adhesion of paint to the substrate after the treatments. Coating performance analyses were also carried out using a Fourier transform infrared spectrometer, water contact angle, and optical microscopic images. The first set of panels was treated with UV radiation for 0, 2, 4 and, 8 days, and the surface wettability was also assessed using the contact angle test. Two coats of paints, including a primer and top coat, were used, and the panels were exposed to UV radiation and immersed in water for 500 hrs and 1000 hrs. It was found that untreated panels showed a much higher contact angle of 106°, whereas the contact angle of panels treated with UV radiation was reduced to 47°. The cross-cut tests showed considerable flaking of the coating along the edges and squares of panels that were not treated, and very small flakes along the edges and parts of the grid square on panels that were UV treated, thus confirming the enhancement of coating adhesion between composite and coating surfaces by UV treatments.

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