scholarly journals Experimental Study of the Influence of the Adsorbate Layer Composition on the Wetting of Different Substrates with Water

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Michaela Heier ◽  
Rolf Merz ◽  
Stefan Becker ◽  
Kai Langenbach ◽  
Michael Kopnarski ◽  
...  

Wetting is strongly influenced by adsorbate layers, which are omnipresent on surfaces. The influence of the composition and thickness of adsorbate layers on the water contact angle of sessile drops on different substrates was systematically investigated in the present work. Measurements were carried out for gold-sputtered substrates. These new results are compared to results from a previous study, in which corresponding measurements were carried out for technical steel and titanium substrates. In all experiments, different pretreatments of the samples were used to obtain variations of the adsorbate layer. The samples were either exposed to an oil bath or not, and different cleaning agents were used. The analysis of the adsorbate layer was carried out with X-ray photoelectron spectroscopy (XPS). The results for the different substrates reveal that the water contact angle depends mainly on the composition of the adsorbate layer. The substrate has only an indirect influence, as it influences the composition of the adsorbate layer. The thickness of the adsorbate layers was between 1.4 and 14 nm and was large enough to prevent a direct influence of the substrate on the water contact angle. It is shown that using the information on the adsorbate layer composition from XPS and the results for the water contact angle obtained for the gold samples alone, the water contact angles on the steel and titanium samples can be predicted.

2006 ◽  
Vol 15-17 ◽  
pp. 187-192 ◽  
Author(s):  
Ko Shao Chen ◽  
Su Chen Chen ◽  
Yi Chun Yeh ◽  
Wei Cheng Lien ◽  
Hong Ru Lin ◽  
...  

Expanded polytetrafluoroethylene (ePTFE) is a bioinert material. To improve the ePTFE film biocompatibility, the cold plasma technology was used with acetic acid as monomer to deposit onto ePTFE film and then (N-isopropylacrylamide) was grafted onto the surface by photo-grafting. The characteristics of the surface were evaluated with X-ray photoelectron spectroscopy (XPS), FTIR and water contact angle. It was found that the contact angle of water on the untreated ePTFE significantly decrease from125° to 72° after ePTFE film being treated with acetic acid plasma deposition treatment. Due to the hydrophilicity of poly(N-isopropylacrylamide), the contact angle of water on the ePTFE-g-NIPAAm approached to 0°.


2011 ◽  
Vol 306-307 ◽  
pp. 1631-1634 ◽  
Author(s):  
Ya Kai Feng ◽  
Da Zhi Yang ◽  
Hai Yang Zhao ◽  
Jin Tang Guo ◽  
Qing Liang Chen ◽  
...  

Poly(3-dimethyl(methacryloyloxyethyl)ammonium propane sulfonate) (poly(DMAPS)) zwitterionic brushes were grafted onto the polycarbonateurethane (PCU) surface to improve its hydrophilicity and hemocompatibility by Ultraviolet (UV) polymerization. Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and water contact angle were used to characterize the chemical and physical properties of the modified PCU surface. DMAPS-grafted PCU films showed significantly high hydrophilicity owing to the high hydrophilic poly(DMAPS) zwitterionic brushes. The cytotoxicity tests revealed the sulfoammonium zwitterionic brushes modified PCU film had good cytocompatibility. In addition, the hemocompatibility of the modified PCU films was evaluated by hemolytic tests and platelet adhesion tests. The PCU films modified with zwitterionic brushes had a lower hemolytic index, showed effective resistance to platelet adhesion. Due to the fact that sulfoammonium zwitterionic brushes can improve the hemocompatibility of the PCU surface, this gives rise to its potential application as blood-contacting materials or devices.


2011 ◽  
Vol 306-307 ◽  
pp. 3-6
Author(s):  
Hai Yang Zhao ◽  
Ya Kai Feng ◽  
Da Zhi Yang ◽  
Jin Tang Guo ◽  
Qing Liang Chen ◽  
...  

In order to improve the hemocompatibility of polycarbonateurethane (PCU), the biomimetic phosphorylcholine (PC) group was introduced onto material surface. Brush structure having PC groups was formed by ultraviolet (UV) initiated polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) to improve the hydrophilicity and hemocompatibility of PCU surfaces. Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electrical microscopy (SEM) and water contact angle were used to characterize the chemical and physical properties of the modified PCU surfaces. Compared with original PCU, the PC-grafted PCU surfaces showed significantly high hydrophilicity as indicating by low water contact angle. The hemocompatibility of the PC-grafted PCU surfaces was evaluated by platelet adhesion test. The PCU surfaces modified with phosphorylcholine zwitterionic brushes showed effective resistance to platelet adhesion and high hemocompatibility. These PC-grafted PCU materials will have potential application as blood-contacting materials or devices due to their good mechanical and hemocompatible properties.


NANO ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. 2050150
Author(s):  
Sifeng Zhang ◽  
Lulu Wang ◽  
Ziguang Zheng ◽  
Yunrui Hei ◽  
Luting Zhou ◽  
...  

In this study, BiOI was successfully synthesized using a hydrothermal method and then modified using hexamethyldisiloxane (HMDS) and polydimethylsiloxane (PDMS), respectively, to achieve a controllable water contact angle (WCA) for these materials. The physical and chemical properties of the modified BiOI were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) method, UV–Vis diffuse reflectance spectroscopy (DRS), Fourier transform infrared (FTIR) spectroscopy and water contact angle (WCA) techniques. Compared with the unmodified BiOI, HMDS- and PDMS-modified BiOI had higher photocatalytic activities for 17[Formula: see text]-ethinylestradiol (EE2) under visible light irradiation for 28 min after reacting in dark for 30 min. When BiOI was modified using HMDS and PDMS, the WCA increased. When the WCA of HMDS- and PDMS-modified BiOI was controlled in the range of 25.3–32.7[Formula: see text] and 38.1–78.5[Formula: see text], respectively, better photocatalytic performances were achieved. When the WCA of modified BiOI was 29.7[Formula: see text] (1.00[Formula: see text]mL HMDS) and 47.8[Formula: see text] (0.20[Formula: see text]mL PDMS), the best photocatalytic performances were achieved with EE2 removal rate of 98.85% and 98.72%, respectively, however, the removal rate of the unmodified BiOI was 85.01%. The reaction rate constants of BiOI (1.00[Formula: see text]mL HMDS) and BiOI (0.20[Formula: see text]mL PDMS) were 2.33 and 2.15 times higher than the unmodified BiOI, respectively. The improved catalytic performances of modified BiOI could be attributed to the synergistic effect of the controlled wettability of BiOI and functional groups on the surface of photocatalysts.


2013 ◽  
Vol 690-693 ◽  
pp. 1636-1640 ◽  
Author(s):  
Te Hsing Wu ◽  
Ko Shao Chen ◽  
Lie Hang Shen

In this study, We immobilized hydrogel material onto expanded polytetrafluoroethylene (ePTFE) film and used as an functional biomaterial. The material is a film containing titanium oxide onto polymer sheet. The hydrogel film is hydrophilic, bacterial inactivated and bio-compatible. In order to improve the ePTFE film biocompatibility, the cold plasma or γ-ray technology was used with acetic acid as monomer to deposit onto ePTFE film and then (N-isopropylacrylamide) was grafted onto the surface by radiation photo-grafting. The characteristics of the material surface were evaluated with X-ray photoelectron spectroscopy (XPS), FTIR and water contact angle. It was found that the contact angle of water on the untreated ePTFE significantly decrease from125° to 72° after ePTFE film being treated with acetic acid plasma deposition procedure. Due to the hydrophilicity of poly (N-isopropylacrylamide), so the contact angle of water on the ePTFE-g-NIPAAm almost approached to 0°. This thermal sensitive ePTFE hydrogels can be applied to artificial guiding tube and wound dressing material.


Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 471 ◽  
Author(s):  
Martha Claros ◽  
Milena Setka ◽  
Yecid P. Jimenez ◽  
Stella Vallejos

Non-modified (ZnO) and modified (Fe2O3@ZnO and CuO@ZnO) structured films are deposited via aerosol assisted chemical vapor deposition. The surface modification of ZnO with iron or copper oxides is achieved in a second aerosol assisted chemical vapor deposition step and the characterization of morphology, structure, and surface of these new structured films is discussed. X-ray photoelectron spectrometry and X-ray diffraction corroborate the formation of ZnO, Fe2O3, and CuO and the electron microscopy images show the morphological and crystalline characteristics of these structured films. Static water contact angle measurements for these structured films indicate hydrophobic behavior with the modified structures showing higher contact angles compared to the non-modified films. Overall, results show that the modification of ZnO with iron or copper oxides enhances the hydrophobic behavior of the surface, increasing the contact angle of the water drops at the non-modified ZnO structures from 122° to 135° and 145° for Fe2O3@ZnO and CuO@ZnO, respectively. This is attributed to the different surface properties of the films including the morphology and chemical composition.


2017 ◽  
Vol 7 ◽  
pp. 184798041770279 ◽  
Author(s):  
Baojiang Liu ◽  
Taizhou Tian ◽  
Jinlong Yao ◽  
Changgen Huang ◽  
Wenjun Tang ◽  
...  

A robust superhydrophobic organosilica sol-gel-based coating on a cotton fabric substrate was successfully fabricated via a cost-effective one-step method. The coating was prepared by modification of silica nanoparticles with siloxane having long alkyl chain that allow to reduce surface energy. The coating on cotton fabric exhibited water contact angle of 151.6°. The surface morphology was evaluated by scanning electron microscopy, and surface chemical composition was measured with X-ray photoelectron spectroscopy. Results showed the enhanced superhydrophobicity that was attributed to the synergistic effect of roughness created by the random distribution of silica nanoparticles and the low surface energy imparted of long-chain alkane siloxane. In addition, the coating also showed excellent durability against washing treatments. Even after washed for 30 times, the specimen still had a water contact angle of 130°, indicating an obvious water-repellent property. With this outstanding property, the robust superhydrophobic coating exhibited a prospective application in textiles and plastics.


2011 ◽  
Vol 396-398 ◽  
pp. 1619-1623
Author(s):  
Zhao Ping Song ◽  
Jun Rong Li ◽  
Hui Ning Xiao

Hydrophobic modification of cellulose fibres was conducted by plasma-induced polymer grafting in an attempt to increase the hydrophobicity of paper. Two hydrophobic monomers, i.e., butyl acrylate (BA) and 2-ethylhexyl acrylate (2-EHA) were grafted on cellulose fibres, induced by atmospheric cold plasma. Various influencing factors associated with the plasma-induced grafting were investigated, including the contact time and reaction temperature with monomers, and the dosage of monomers. Contact-angle measurement, infrared spectrum (IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were used to ascertain the occurrence of the grafting. The results showed that the hydrophobic property of the modified paper sheet was improved significantly after the plasma-induced grafting. The water contact angle on the surface of the paper reached up to higher than125°.


1997 ◽  
Vol 11 (4) ◽  
pp. 388-394 ◽  
Author(s):  
H.C. Van Der Mei ◽  
H.J. Busscher

Physicochemical and structural properties of microbial cell surfaces play an important role in their adhesion to surfaces and are determined by the chemical composition of the outermost cell surface. Many traditional methods used to determine microbial cell wall composition require fractionation of the organisms and consequently do not yield information about the composition of the outermost cell surface. X-ray photoelectron spectroscopy (XPS) measures the elemental composition of the outermost cell surfaces of micro-organisms. The technique requires freeze-drying of the organisms, but, nevertheless, elemental surface concentration ratios of oral streptococcal cell surfaces with peritrichously arranged surface structures showed good relationships with physicochemical properties measured under physiological conditions, such as zeta potentials. Isoelectric points ap-peared to be governed by the relative abundance of oxygen- and nitrogen-containing groups on the cell surfaces. Also, the intrinsic microbial cell-surface hydrophobicity by water contact angles related to the cell-surface composition as by XPS and was highest for strains with an elevated isoelectric point. Inclusion of elemental surface compositions for tufted streptococcal strains caused deterioration of the relationships found. Interestingly, hierarchical cluster analysis on the basis of the elemental surface compositions revealed that, of 36 different streptococcal strains, only four S. rattus as well as nine S. mitis strains were located in distinct groups, well separated from the other streptococcal strains, which were all more or less mixed in one group.


1995 ◽  
Vol 383 ◽  
Author(s):  
M. R. Houston ◽  
R. T. Howe ◽  
K Komvopoulos ◽  
R. Maboudian

ABSTRACTThe surface properties of diamond-like carbon (DLC) films deposited by a vacuum arc technique on smooth silicon wafers are presented with specific emphasis given to stiction reduction in microelectromechanical systems (MEMS). The low deposition temperatures afforded by the vacuum arc technique should allow for easy integration of the DLC films into the current fabrication process of typical surface micromachines by means of a standard lift-off processing technique. Using X-ray photoelectron spectroscopy (XPS), contact angle analysis, and atomic force microscopy (AFM), the surface chemistry, microroughness, hydrophobicity, and adhesion forces of DLC-coated Si(100) surfaces were measured and correlated to the measured water contact angles. DLC films were found to be extremely smooth and possess a water contact angle of 87°, which roughly corresponds to a surface energy of 22 mJ/m2. It is shown that the pull-off forces measured by AFM correlate well with the predicted capillary forces. Pull-off forces are reduced on DLC surfaces by about a factor of five compared to 10 nN pull-off forces measured on the RCA-cleaned silicon surfaces. In the absence of meniscus forces, the overall adhesion force is expected to decrease by over an order of magnitude to the van der Waals attractive force present between two DLC-coated surfaces- To further improve the surface properties of DLC, films were exposed to a fluorine plasma which increased the contact angle to 99° and lowered the pull-off force by approximately 20% over that obtained with as-deposited DLC. The significance of these results is discussed with respect to stiction reduction in micromachines.


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