A Mild Method for Surface-Grafting PEG Onto Segmented Poly(Ester-Urethane) Film with High Grafting Density for Biomedical Purpose

In the paper, poly(ethylene glycol) (PEG) was grafted on the surface of poly(ester-urethane) (SPEU) film with high grafting density for biomedical purposes. The PEG-surface-grafted SPEU (SPEU-PEG) was prepared by a three-step chemical treatment under mild-reaction conditions. Firstly, the SPEU film surface was treated with 1,6-hexanediisocyanate to introduce -NCO groups on the surface with high density (5.28 × 10−7 mol/cm2) by allophanate reaction; subsequently, the -NCO groups attached to SPEU surface were coupled with one of -NH2 groups of tris(2-aminoethyl)amine via condensation reaction to immobilize -NH2 on the surface; finally, PEG with different molecular weight was grafted on the SPEU surface through Michael addition between terminal C = C bond of monoallyloxy PEG and -NH2 group on the film surface. The chemical structure and modified surface were characterized by FT-IR, 1H NMR, X-ray photoelectron spectroscopy (XPS), and water contact angle. The SPEU-PEGs displaying much lower water contact angles (23.9–21.8°) than SPEU (80.5°) indicated that the hydrophilic PEG chains improved the surface hydrophilicity significantly. The SPEU-PEG films possessed outstanding mechanical properties with strain at break of 866–884% and ultimate stress of 35.5–36.4 MPa, which were slightly lower than those of parent film, verifying that the chemical treatments had minimum deterioration on the mechanical properties of the substrate. The bovine serum albumin adsorption and platelet adhesion tests revealed that SPEU-PEGs had improved resistance to protein adsorption (3.02–2.78 μg/cm2) and possessed good resistance to platelet adhesion (781–697 per mm2), indicating good surface hemocompatibility. In addition, due to the high grafting density, the molecular weight of surface-grafted PEG had marginal effect on the surface hydrophilicity and hemocompatibility.

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P4VP Modified Zwitterionic Polymer for the Preparation of Antifouling Functionalized Surfaces

Nanomaterials ◽

10.3390/nano9050706 ◽

2019 ◽

Vol 9 (5) ◽

pp. 706 ◽

Cited By ~ 5

Author(s):

Chaoqun Wu ◽

Yudan Zhou ◽

Haitao Wang ◽

Jianhua Hu

Keyword(s):

Photoelectron Spectroscopy ◽

Cell Attachment ◽

Raft Polymerization ◽

Polymer Brush ◽

Contact Angles ◽

Polymerization Process ◽

Water Contact ◽

Zwitterionic Polymers ◽

Ito Glass ◽

Zwitterionic Polymer

Zwitterionic polymers are suitable for replacing poly(ethylene glycol) (PEG) polymers because of their better antifouling properties, but zwitterionic polymers have poor mechanical properties, strong water absorption, and their homopolymers should not be used directly. To solve these problems, a reversible-addition fragmentation chain transfer (RAFT) polymerization process was used to prepare copolymers comprised of zwitterionic side chains that were attached to an ITO glass substrate using spin-casting. The presence of 4-vinylpyridine (4VP) and zwitterion chains on these polymer-coated ITO surfaces was confirmed using 1H NMR, FTIR, and GPC analyses, with successful surface functionalization confirmed using water contact angle, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) studies. Changes in water contact angles and C/O ratios (XPS) analysis demonstrated that the functionalization of these polymers with β-propiolactone resulted in hydrophilic mixed 4VP/zwitterionic polymers. Protein adsorption and cell attachment assays were used to optimize the ratio of the zwitterionic component to maximize the antifouling properties of the polymer brush surface. This work demonstrated that the antifouling surface coatings could be readily prepared using a “P4VP-modified” method, that is, the functionality of P4VP to modify the prepared zwitterionic polymer. We believe these materials are likely to be useful for the preparation of biomaterials for biosensing and diagnostic applications.

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Engineering the Surface and Mechanical Properties of Water Desalination Membranes Using Ultralong Carbon Nanotubes

Membranes ◽

10.3390/membranes8040106 ◽

2018 ◽

Vol 8 (4) ◽

pp. 106 ◽

Cited By ~ 5

Author(s):

Yehia M. Manawi ◽

Kui Wang ◽

Viktor Kochkodan ◽

Daniel J. Johnson ◽

Muataz A. Atieh ◽

...

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Aspect Ratio ◽

Water Flux ◽

Contact Angles ◽

Water Desalination ◽

Membrane Properties ◽

Porous Membranes ◽

Water Contact ◽

And Performance

In this work, novel polysulphone (PS) porous membranes for water desalination, incorporated with commercial and produced carbon nanotubes (CNT), were fabricated and analyzed. It was demonstrated that changing the main characteristics of CNT (e.g., loading in the dope solutions, aspect ratio, and functionality) significantly affected the membrane properties and performance including porosity, water flux, and mechanical and surface properties. The water flux of the fabricated membranes increased considerably (up to 20 times) along with the increase in CNT loading. Conversely, yield stress and Young’s modulus of the membranes dropped with the increase in the CNT loading mainly due to porosity increase. It was shown that the elongation at fracture for PS/0.25 wt. % CNT membrane was much higher than for pristine PS membrane due to enhanced compatibility of commercial CNTs with PS matrix. More pronounced effect on membrane’s mechanical properties was observed due to compatibility of CNTs with PS matrix when compared to other factors (i.e., changes in the CNT aspect ratio). The water contact angle for PS membranes incorporated with commercial CNT sharply decreased from 73° to 53° (membrane hydrophilization) for membranes with 0.1 and 1.0 wt. % of CNTs, while for the same loading of produced CNTs the water contact angles for the membrane samples increased from 66° to 72°. The obtained results show that complex interplay of various factors such as: loading of CNT in the dope solutions, aspect ratio, and functionality of CNT. These features can be used to engineer membranes with desired properties and performance.

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Synthesis of amphiphilic ABA triblock oligomer via ATRP and its surface properties

Canadian Journal of Chemistry ◽

10.1139/cjc-2016-0591 ◽

2017 ◽

Vol 95 (5) ◽

pp. 605-611 ◽

Cited By ~ 1

Author(s):

Lei Wang ◽

Shaoqing Wen ◽

Zhanxiong Li

Keyword(s):

Photoelectron Spectroscopy ◽

Microphase Separation ◽

Gel Permeation Chromatography ◽

Contact Angles ◽

Chemical Compositions ◽

Water Contact ◽

Force Microscopy ◽

Atomic Force ◽

Poly Ethylene ◽

Magnetic Resonances

A series of novel amphiphilic ABA-type poly(tridecafluorooctylacrylate)-poly(ethylene glycol)-poly(tridecafluorooctylacrylate) (henceforth referred to as p-TDFA-PEG-p-TDFA) triblock oligomers were successfully synthesized via atom transfer radical polymerization (ATRP) using well-defined Br-PEG-Br as macroinitiator and copper as catalyst. The block oligomers were characterized by Fourier transform infrared (FTIR) spectroscopy and 1H and 19F nuclear magnetic resonances (NMR). Gel permeation chromatography (GPC) showed that the block oligomers have been obtained with narrow molecular weight distributions of 1.22–1.33. X-ray photoelectron spectroscopy (XPS) was carried out to confirm the attachment of p-TDFA-PEG-p-TDFA onto the silicon substrate, together with the chemical compositions of p-TDFA-PEG-p-TDFA. The wetabilities of the oligomer films were measured by water contact angles (CAs). Water CAs of p-TDFA-PEG-p-TDFA film were measured and their morphologies were tested by atomic force microscopy (AFM). The result showed that the CAs of the oligomer films, which possess fluoroalkyl groups assembled on the outer surface, increase after heating due to the migration of fluoroalkyl groups and the resulted microphase separation of the p-TDFA-PEG-p-TDFA.

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Facile fabrication of photoinduced superhydrophobic–superhydrophilic surfaces on cellulose substrate without strength loss

Textile Research Journal ◽

10.1177/0040517518779251 ◽

2018 ◽

Vol 89 (9) ◽

pp. 1807-1822

Author(s):

Yunjie Yin ◽

Yanyan Zhang ◽

Xiaoqian Ji ◽

Tao Zhao ◽

Chaoxia Wang

Keyword(s):

Mechanical Properties ◽

Uv Irradiation ◽

Uv Curing ◽

Contact Angles ◽

Curing Process ◽

Water Contact ◽

Cellulose Substrate ◽

Cellulose Substrates ◽

Uv Curing Process ◽

Modified Cellulose

A novel strategy was reported on the design and fabrication of functional photosensitive hybrid sols (FPHSs) by non-alcoholic emulsification in the presence of a TiO2 nanoparticle and photoinitiator via a sol-gel process using tetraethylorthosilicate, γ-methacryloxypropyltrimethoxysilane (MPS) and hydrophobic silane coupling agents as precursors. Smart cellulose substrates with alterable superhydrophobic–superhydrophilic conversion were fabricated using FPHS via the ultraviolet (UV) curing process. The liquid FPHS was photocured into solid gel during UV irradiation for 40 s with MPSs in FPHS, which was verified via Fourier transform infrared spectra. The cellulose substrates were modified with FPHSs, and the water contact angles of the modified cellulose substrates were more than 150°. The superhydrophobicity was improved by the gathering of hydrophobic chains and particle deposition of hybrid gel on the fiber surface. Nevertheless, the water contact angles of the modified cellulose substrates were receded with UV irradiation from 158° to 0° in 200 min, due to TiO2 photoinduction. The irradiated cellulose substrates were placed in the dark, and the water contact angles were recovered to about 130°, gradually. What is more, the reversible process can be repeated more than eight times. The modified cellulose substrate presented excellent washing fastness, even suffering 10 times washing processing. The mechanical properties, including breaking strength and elongation rate, were improved after the coating and UV curing process, which considerably remedied the defects of the heating curing process on the mechanical properties.

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Surface Properties of Pine Scrimber Panels with Varying Density

Coatings ◽

10.3390/coatings9060397 ◽

2019 ◽

Vol 9 (6) ◽

pp. 397 ◽

Cited By ~ 2

Author(s):

Jinguang Wei ◽

Qiuqin Lin ◽

Yahui Zhang ◽

Wenji Yu ◽

Chung-Yun Hse ◽

...

Keyword(s):

Surface Roughness ◽

Surface Properties ◽

Photoelectron Spectroscopy ◽

Lower Surface ◽

Contact Angles ◽

High Density ◽

Water Contact ◽

Change Rate ◽

Hydrophilic Material ◽

Wood Grain

Coating quality for scrimber products against exterior conditions is largely dependent on the surface properties. The wettability, morphology, and chemical composition of pine scrimber surfaces were investigated to better understand the surface properties. The scrimber was found to be a hydrophilic material because the water contact angles were less than 90°. The panels with a density of 1.20 g/cm3 had the largest angle change rate (k = 0.212). As the panel density increased, the instantaneous contact angle of each test liquid (i.e., water, formamide, and diiodomethane) on the panels decreased, and so did surface free energy. Panels with higher density showed lower surface roughness. Surface roughness across the wood grain was greater than that along the grain. SEM observations showed the high-density panels had a smoother surface with fewer irregular grooves in comparison with the low-density panels. X-ray photoelectron spectroscopy (XPS) analysis indicated that more unoxygenated groups appeared on the surface of high-density panels.

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Functionalization of Neutral Polypropylene by Using Low Pressure Plasma Treatment: Effects on Surface Characteristics and Adhesion Properties

Polymers ◽

10.3390/polym11020202 ◽

2019 ◽

Vol 11 (2) ◽

pp. 202 ◽

Cited By ~ 10

Author(s):

Chiara Mandolfino ◽

Enrico Lertora ◽

Carla Gambaro ◽

Marco Pizzorni

Keyword(s):

Surface Morphology ◽

Photoelectron Spectroscopy ◽

Polymeric Materials ◽

Low Pressure ◽

Contact Angles ◽

Bonded Joints ◽

Water Contact ◽

Adhesion Properties ◽

Pressure Plasma ◽

Low Pressure Plasma

Polyolefins are considered among the most difficult polymeric materials to treat because they have poor adhesive properties and high chemical barrier responses. In this paper, an in-depth study is reported for the low pressure plasma (LPP) treatment of neutral polypropylene to improve adhesion properties. Changes in wettability, chemical species, surface morphology and roughness of the polypropylene surfaces were evaluated by water contact angle measurement, X-ray photoelectron spectroscopy and, furthermore, atomic force microscopy (AFM). Finally, the bonded joints were subjected to tensile tests, in order to evaluate the practical effect of changes in adhesion properties. The results indicate that plasma is an effective treatment for the surface preparation of polypropylene for the creation of bonded joints: contact angles decreased significantly depending on the plasma-parameter setup, surface morphology was also found to vary with plasma power, exposure time and working gas.

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UV-Curable Hydrophobic Coatings of Functionalized Carbon Microspheres with Good Mechanical Properties and Corrosion Resistance

Coatings ◽

10.3390/coatings8120439 ◽

2018 ◽

Vol 8 (12) ◽

pp. 439 ◽

Cited By ~ 2

Author(s):

Jiajia Wen ◽

Chengchen Feng ◽

Huijie Li ◽

Xinghai Liu ◽

Fuyuan Ding ◽

...

Keyword(s):

Mechanical Properties ◽

Corrosion Resistance ◽

Thermogravimetric Analysis ◽

Photoelectron Spectroscopy ◽

Carbon Microspheres ◽

Sem Images ◽

Water Contact ◽

Pencil Hardness ◽

Uv Curable ◽

Functional Product

Polyurethane acrylates (PUAs) are a kind of UV curable prepolymer with excellent comprehensive performance. However, PUAs are highly hydrophilic and when applied outdoors, presenting serious problems caused by rain such as discoloring, losing luster and blistering. Thus, it’s important to improve their hydrophobicity and resistance against corrosion. In this paper, carbon microspheres (CMSs) were modified through chemical grafting method. Active double bonds were introduced onto the surface of organic carbon microspheres (OCMSs) and the functional product was referred to as FCMS. The results of Transmission Electron Microscope (TEM), X-ray Photoelectron Spectroscopy (XPS) and Thermogravimetric analysis (TGA) showed that organic chain segments were successfully connected to the surface of OCMSs and the grafting efficiency was as high as 16%. FCMSs were successfully added into UV-curable polyurethane acrylate prepolymer to achieve a hydrophobic coating layer with good mechanical properties, thermal stability and corrosion resistance. When the addition of FCMSs were 1%, thermogravimetric analysis (TGA) results showed that 5% of the initial mass was lost at 297 °C. The water absorption decreased from 52% to 38% and the water contact angle of the PUA composite increased from 72° to 106°. The pencil hardness increased to 4H and obvious crack termination phenomenon was observed in SEM images. Moreover, the corrosion rate was decreased from 0.124 to 0.076 mm/a.

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The Use of X-Ray Photoelectron Spectroscopy for the Study of Oral Streptococcal Cell Surfaces

Advances in Dental Research ◽

10.1177/08959374970110040301 ◽

1997 ◽

Vol 11 (4) ◽

pp. 388-394 ◽

Cited By ~ 5

Author(s):

H.C. Van Der Mei ◽

H.J. Busscher

Keyword(s):

Cell Surface ◽

Photoelectron Spectroscopy ◽

Surface Composition ◽

Cell Surface Hydrophobicity ◽

Surface Hydrophobicity ◽

Contact Angles ◽

Microbial Cell ◽

Cell Surfaces ◽

Water Contact ◽

X Ray

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.

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Diamond-Like Carbon Films for Silicon Passivation in Microelectromechanical Devices

MRS Proceedings ◽

10.1557/proc-383-391 ◽

1995 ◽

Vol 383 ◽

Cited By ~ 27

Author(s):

M. R. Houston ◽

R. T. Howe ◽

K Komvopoulos ◽

R. Maboudian

Keyword(s):

Contact Angle ◽

Surface Properties ◽

Photoelectron Spectroscopy ◽

Microelectromechanical Systems ◽

Adhesion Force ◽

Contact Angles ◽

Vacuum Arc ◽

Diamond Like Carbon ◽

Adhesion Forces ◽

Water Contact

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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PVDF Films with Superhydrophobic Surface Fabricated by Plasma-Enhanced Chemical Vapor Deposition

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.1451 ◽

2009 ◽

Vol 79-82 ◽

pp. 1451-1454 ◽

Cited By ~ 1

Author(s):

Zhi Qiu Zhang ◽

Wen Fang Yang ◽

Zhen Ya Gu ◽

Rui Ting Huo

Keyword(s):

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Film Surface ◽

Chemical Vapor ◽

Contact Angles ◽

Water Repellent ◽

Treatment Technology ◽

Water Contact ◽

Lotus Effect ◽

Pvdf Membrane

Lotus effect is well-known to be governed by chemical properties and nanotextures of the surfaces. In this paper, a method with two-steps treatment technology was applied to develop the superhydrophobic polyvinylidene fruoride(PVDF) membrane with the property of anti-contamination and self-cleaning. First, the PVDF membrane was treated by oxygen plasma so as to get the reactive groups. Second, this film was deposited by perfluoroalkylethyl acrylate precursor/Ar gas via plasma-enhanced chemical vapor deposition (PECVD). The modified film surface exhibited ultra water-repellent ability, showing that the water contact angles was larger than 150 °and the dynamic contact angles was usually lower than 5°.

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