Siloxane-Starch-Based Hydrophobic Coating for Multiple Recyclable Cellulosic Materials

The results of the application of a new hydrophobization agent based on a triethoxymethylsilane and standard starch aqueous mixture for mass-produced cellulosic materials—printing paper, paperboard, and sack paper—have been evaluated to examine whether such a mixture can be used in industrial practice. The application of this agent on laboratory sheets prepared in a repetitive recycling process was performed to investigate its influence on the formation and properties of the products, as well as the contamination of circulating water. Measurements of the water contact angle, Cobb tests, and water penetration dynamics (PDA) were performed to test the barrier properties of the resulting materials. The effects of the applied coatings and recycling process on the paper’s tensile strength, tear index, roughness, air permeance, and ISO brightness were studied. Studies have proven that this formulation imparts relatively high surface hydrophobicity to all materials tested (contact angles above 100°) and a significant improvement in barrier properties while maintaining good mechanical and optical performance. The agent also does not interfere with the pulping and re-forming processes during recycling and increases circulation water contamination to an acceptable degree. Attenuated total reflectance Fourier-transform infrared (FT-IR) spectra of the paper samples revealed the presence of a polysiloxane network on the surface.

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Improvement of Paper Resistance against Moisture and Oil by Coating with Poly(-3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and Polycaprolactone (PCL)

Applied Sciences ◽

10.3390/app11178058 ◽

2021 ◽

Vol 11 (17) ◽

pp. 8058

Author(s):

Emanuela Lo Faro ◽

Camilla Menozzi ◽

Fabio Licciardello ◽

Patrizia Fava

Keyword(s):

Barrier Properties ◽

Surface Hydrophobicity ◽

Contact Angles ◽

Future Research ◽

Water Contact ◽

Contact Materials ◽

Paper Coatings ◽

Angle Measurements ◽

Oil Resources ◽

Plain Paper

Surface hydrophobicity and grease resistance of paper may be achieved by the application of coatings usually derived from fossil-oil resources. However, poor recyclability and environmental concerns on generated waste has increased interest in the study of alternative paper coatings. This work focuses on the study of the performances offered by two different biopolymers, poly(3-hydroxybutyrate-co-3hydroxyvalerate) (PHBV) and polycaprolactone (PCL), also assessing the effect of a plasticizer (PEG) when used as paper coatings. The coated samples were characterized for the structural (by scanning electron microscopy, SEM), diffusive (water vapor and grease barrier properties), and surface properties (affinity for water and oil, by contact angle measurements). Samples of polyethylene-coated and fluorinated paper were used as commercial reference. WVTR of coated samples generally decreased and PHBV and PCL coatings with PEG at 20% showed interesting low wettability, as inferred from the water contact angles. Samples coated with PCL also showed increased grease resistance in comparison with plain paper. This work, within the limits of its lab-scale, offers interesting insights for future research lines toward the development of cellulose-based food contact materials that are fully recyclable and compostable.

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The Effect of Hydroxyl on the Superhydrophobicity of Dodecyl Methacrylate (LMA) Coated Fabrics through Simple Dipping-Plasma Crosslinked Method

Coatings ◽

10.3390/coatings10121263 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1263

Author(s):

Liyun Xu ◽

Yu Zhang ◽

Ying Guo ◽

Ruiyun Zhang ◽

Jianjun Shi ◽

...

Keyword(s):

Thermoplastic Polyurethane ◽

Hydrophobic Effect ◽

Surface Hydrophobicity ◽

Contact Angles ◽

Binding Property ◽

Interesting Phenomenon ◽

Water Contact ◽

Capacitively Coupled ◽

Pet Fabric ◽

Dodecyl Methacrylate

In order to obtain stable superhydrophobicity, suitable hydrophobic treatment agents should be selected according to different material properties. In this paper, cotton and poly(ethylene terephthalate) (PET) fabrics were respectively coated with dodecyl methacrylate (LMA) via argon combined capacitively coupled plasma (CCP), and the surface hydrophobicity and durability of the treated cotton and polyester fabrics are also discussed. An interesting phenomenon happened, whereby the LMA-coated cotton fabric (Cotton-g-LMA) had better water repelling and mechanical durability properties than LMA-coated PET fabric (PET-g-LMA), and LMA-coated hydroxyl-grafted PET fabrics (PET fabrics were successively coated with polyethylene glycol (PEG) and LMA, PET-g-PEG & LMA) had a similar performance to cotton fabrics. The water contact angles of Cotton-g-LMA, PET-g-LMA and PET-g-PEG & LMA were 156°, 153° and 155°, respectively, and after 45 washing cycles or 1000 rubbing cycles, the corresponding water contact angles decreased to 145°, 88°, 134° and 146°, 127° and 143°, respectively. Additionally, thermoplastic polyurethane (TPU) and polyamides-6 (PA6) fabrics all exhibited the same properties as the PET fabric. Therefore, the grafting of hydroxyl can improve the hydrophobic effect of LMA coating and the binding property between LMA and fabrics effectively, without changing the wearing comfort.

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Integration of Polypyrrole Electrode into Piezoelectric PVDF Energy Harvester with Improved Adhesion and Over-Oxidation Resistance

Polymers ◽

10.3390/polym11061071 ◽

2019 ◽

Vol 11 (6) ◽

pp. 1071

Author(s):

Kyungha Baik ◽

Sohyun Park ◽

Changsang Yun ◽

Chung Hee Park

Keyword(s):

Energy Harvester ◽

Chemical Vapor ◽

Aluminum Foil ◽

Surface Hydrophobicity ◽

Alkaline Treatment ◽

Electrode System ◽

Pvdf Film ◽

Smart Textiles ◽

Water Contact ◽

Hydrophobic Coating

Smart textiles for wearable devices require flexibility and a lightweight, so in this study, a soft polypyrrole (PPy) electrode system was integrated into a piezoelectric polyvinylidenefluoride (PVDF) energy harvester. The PVDF energy harvester integrated with a PPy electrode had the piezoelectric output voltage of 4.24–4.56 V, while the PVDF energy harvester with an additional aluminum-foil electrode exhibited 2.57 V. Alkaline treatment and chemical vapor deposition with n-dodecyltrimethoxysilane (DTMS) were employed to improve the adhesion between the PVDF and PPy and the resistance to over-oxidation in aqueous solutions. The PVDF film modified by an alkaline treatment could have the improved adhesion via the introduction of polar functional groups to its surface, which was confirmed by the ultrasonication. The surface hydrophobicity of the PPy electrode was enhanced by the DTMS coating, resulting in the improvement of the resistance to over-oxidation with a water contact angle of 111°. Even with the hydrophobic coating, the electrodes remained electroconductive and continued to transfer an electric charge, maintaining the piezoelectricity of the PVDF film. The developed electrode-integrated energy harvester is expected to be applied to smart textiles because it offers the advantages of efficient piezoelectric generation, flexibility, and durability.

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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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Mucin Coating on Hydrophobic Polymer Materials

MRS Proceedings ◽

10.1557/proc-599-299 ◽

1999 ◽

Vol 599 ◽

Author(s):

L. Shi ◽

K. D. Caldwell

Keyword(s):

Submaxillary Gland ◽

Surface Concentration ◽

Surface Hydrophobicity ◽

Contact Angles ◽

Polymer Materials ◽

Adsorption Model ◽

Kinetics Parameters ◽

Water Contact ◽

Long Term Observation

AbstractIn this work, the adsorption isotherm and kinetics of bovine submaxillary gland mucin (BSM) onto a hydrophobic polystyrene surface were studied by the solution depletion method, in which mucin surface concentrations were analyzed by amino acid analysis. Using a Langmuir adsorption model and non-linear curve fitting, kinetics parameters, kon and koff were determined. The coating was found to be very stable with very limited desorption (less than 2%) from a long term observation. By measuring the water contact angles, the changes in surface hydrophobicity due to mucin coating were monitored on four polymer materials, namely polymethylmethacrylate (PMMA), polyurethane (PU), polystyrene (PS), and silicone. After coating, all the hydrophobic surfaces turned into very hydrophilic. A strict correlation between mucin surface concentration and surface wettability has been found.

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Bacterial factors influencing adhesion of Pseudomonas aeruginosa strains to a poly(ethylene oxide) brush

Microbiology ◽

10.1099/mic.0.29005-0 ◽

2006 ◽

Vol 152 (9) ◽

pp. 2673-2682 ◽

Cited By ~ 71

Author(s):

Astrid Roosjen ◽

Henk J. Busscher ◽

Willem Norde ◽

Henny C. van der Mei

Keyword(s):

Pseudomonas Aeruginosa ◽

Ethylene Oxide ◽

Cell Surface Hydrophobicity ◽

Surface Hydrophobicity ◽

Contact Angles ◽

Bacterial Strains ◽

Water Contact ◽

Poly Ethylene Oxide ◽

Poly Ethylene ◽

Brush Coating

Most bacterial strains adhere poorly to poly(ethylene oxide) (PEO)-brush coatings, with the exception of a Pseudomonas aeruginosa strain. The aim of this study was to find factors determining whether P. aeruginosa strains do or do not adhere to a PEO-brush coating in a parallel plate flow chamber. On the basis of their adhesion, a distinction could be made between three adhesive and three non-adhesive strains of P. aeruginosa, while bacterial motilities and zeta potentials were comparable for all six strains. However, water contact angles indicated that the adhesive strains were much more hydrophobic than the non-adhesive strains. Furthermore, only adhesive strains released surfactive extracellular substances, which may be engaged in attractive interactions with the PEO chains. Atomic force microscopy showed that the adhesion energy, measured from the retract curves of a bacterial-coated cantilever from a brush coating, was significantly more negative for adhesive strains than for non-adhesive strains (P<0.001). Through surface thermodynamic and extended-DLVO (Derjaguin, Landau, Verwey, Overbeek) analyses, these stronger adhesion energies could be attributed to acid–base interactions. However, the energies of adhesion of all strains to a brush coating were small when compared with their energies of adhesion to a glass surface. Accordingly, even the adhesive P. aeruginosa strains could be easily removed from a PEO-brush coating by the passage of a liquid–air interface. In conclusion, cell surface hydrophobicity and surfactant release are the main factors involved in adhesion of P. aeruginosa strains to PEO-brush coatings.

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Tailoring Surface Hydrophobicity of Commercial Polyimide by Laser-Induced Nanocarbon Texturing

Journal of Micro and Nano-Manufacturing ◽

10.1115/1.4048600 ◽

2020 ◽

Vol 8 (3) ◽

Author(s):

Moataz Abdulhafez ◽

Angela J. McComb ◽

Mostafa Bedewy

Keyword(s):

Contact Angle ◽

Surface Characterization ◽

Surface Engineering ◽

Processing Parameters ◽

Surface Hydrophobicity ◽

Spot Size ◽

Contact Angles ◽

Water Contact ◽

Wide Range ◽

Surface Nanostructure

Abstract The growth of laser-induced nanocarbons, referred to here as laser-induced nanocarbon (LINC) for short, directly on polymeric surfaces is a promising route toward surface engineering of commercial polymers. This paper aims to demonstrate how this new approach can enable achieving varied surface properties based on tuning the nanostructured morphology of the formed graphitic material on commercial polyimide (Kapton) films. We elucidate the effects of tuning laser processing parameters on the achieved nanoscale morphology and the resulting surface hydrophobicity or hydrophilicity. Our results show that by varying lasing power, rastering speed, laser spot size, and line-to-line gap sizes, a wide range of water contact angles are possible, i.e., from below 20 deg to above 110 deg. Combining water contact angle measurements from an optical tensiometer with LINC surface characterization using optical microscopy, electron microscopy, and Raman spectroscopy enables building the process–structur–property relationship. Our findings reveal that both the value of contact angle and the anisotropic wetting behavior of LINC on polyimide are dependent on their hierarchical surface nanostructure which ranges from isotropic nanoporous morphology to fibrous morphology. Results also show that increasing gap sizes lead to an increase in contact angles and thus an increase in the hydrophobicity of the surface. Hence, our work highlight the potential of this approach for manufacturing flexible devices with tailored surfaces.

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Impact of Air Exposure Time on the Water Contact Angles of Daily Disposable Silicone Hydrogels

International Journal of Molecular Sciences ◽

10.3390/ijms20061313 ◽

2019 ◽

Vol 20 (6) ◽

pp. 1313 ◽

Cited By ~ 5

Author(s):

Petar Eftimov ◽

Norihiko Yokoi ◽

Nikola Peev ◽

Georgi Georgiev

Keyword(s):

Surface Coating ◽

Sessile Drop ◽

High Surface ◽

Tear Film ◽

Contact Angles ◽

Water Contact ◽

Air Exposure ◽

Film Stability ◽

Silicone Hydrogel ◽

Silicone Hydrogels

The wettability of silicone hydrogel (SiHy) contact lens (CLs) is crucial for the pre-lens tear film stability throughout the day. Therefore, sessile drop and captive bubble setups were used to study the advancing and receding water contact angles (CA) of four SiHy materials: narafilcon A (TE), senofilcon A (AOD), stenfilcon A (MD), and delefilcon A (DT). TE and AOD have 48% and 38% water content, respectively, and no surface coating. MD (54% water) implements “smart chemistry” with just 4.4% bulk silicone content, while DT has >80% water at its surface. These SiHy were subjected to continuous blink-like air exposure (10 s)/rehydration (1s) cycles for 0, 1, 2, 3, 4, 6, 8, 10, 12, 14, and 16 h. The advancing CA, which measures the rehydration propensity of the CL surface, proved to be the most sensitive parameter to discriminate between the samples. The order of performance for the entire time scale was DT > MD >> AOD ≥ TE. The extended desiccation/rehydration cycling increased the differences between the CA of DT and MD compared to AOD and TE. This suggests that the low Si surface content and the high surface hydration are major determinants of SiHy wettability.

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Active Barrier Coating for Packaging Paper with Controlled Release of Sunflower Oils

Molecules ◽

10.3390/molecules26123561 ◽

2021 ◽

Vol 26 (12) ◽

pp. 3561

Author(s):

Pieter Samyn

Keyword(s):

Controlled Release ◽

Surface Composition ◽

Barrier Properties ◽

Organic Coating ◽

Contact Angles ◽

Water Contact ◽

Chemical Surface ◽

Oil Resistance ◽

Thermal Release ◽

Sunflower Oils

The use of paper as a sustainable packaging material is favored, but it lacks sufficient barrier properties in terms of water repellence and oil resistance. Novel approaches consider active packaging materials or coatings with controlled release providing additional functionality for delivery of specific components to the surface. In this study, the development of a waterborne coating with organic nanoparticles and encapsulated sunflower oils is presented as a system for thermal release of the oil and on-demand tuning of the final barrier properties of the paper substrate. After synthesis of the nanoparticles, it seems that the encapsulation of various grades of sunflower oil (i.e., either poly-unsaturated or mono-unsaturated) strongly affects the encapsulation efficiency and thermal release profiles. The water contact angles are controlled by the oil release and chemical surface composition of the coating upon thermal heating. The oil resistance of the paper improves as a more continuous oil film is formed during thermal release. In particular, the chemical surface composition of the paper coatings is detailed by means of micro-Raman spectroscopy and surface imaging, which provide an analytical quantification tool to evaluate surface coverage, oil delivery, and variations in organic coating moieties.

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Three-Dimensional Soft Material Micropatterning via Grayscale Photolithography for Improved Hydrophobicity of Polydimethylsiloxane (PDMS)

Micromachines ◽

10.3390/mi13010078 ◽

2022 ◽

Vol 13 (1) ◽

pp. 78

Author(s):

Intan Sue Liana Abdul Hamid ◽

Beh Khi Khim ◽

Mohammad Faiz Mohamed Omar ◽

Khairu Anuar Mohamad Zain ◽

Nuha Abd Rhaffor ◽

...

Keyword(s):

Pure Water ◽

Three Dimensional ◽

Surface Hydrophobicity ◽

Contact Angles ◽

Master Mold ◽

Water Contact ◽

Pdms Surface ◽

Lithography Technique ◽

Scanning Electron ◽

Micropillar Arrays

In this present work, we aim to improve the hydrophobicity of a polydimethylsiloxane (PDMS) surface. Various heights of 3D PDMS micropillars were fabricated via grayscale photolithography, and improved wettability was investigated. Two approaches of PDMS replication were demonstrated, both using a single master mold to obtain the micropillar arrays. The different heights of fabricated PDMS micropillars were characterized by scanning electron microscopy (SEM) and a surface profiler. The surface hydrophobicity was characterized by measuring the water contact angles. The fabrication of PDMS micropillar arrays was shown to be effective in modifying the contact angles of pure water droplets with the highest 157.3-degree water contact angle achieved by implementing a single mask grayscale lithography technique.

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