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

Polymers ◽  
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.

scholarly journals A Green Approach to Modify Surface Properties of Polyurethane Foam for Enhanced Oil Absorption

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1883 ◽  
Author(s):  
Zhi Chien Ng ◽  
Rosyiela Azwa Roslan ◽  
Woei Jye Lau ◽  
Mehmet Gürsoy ◽  
Mustafa Karaman ◽  
...  
Keyword(s):  
Surface Properties ◽  
Positive Impact ◽  
Chemical Vapor ◽  
Surface Hydrophobicity ◽  
Absorption Efficiency ◽  
Oil Absorption ◽  
Water Contact ◽  
Green Approach ◽  
Pu Foam ◽  
Modify Surface

The non-selective property of conventional polyurethane (PU) foam tends to lower its oil absorption efficiency. To address this issue, we modified the surface properties of PU foam using a rapid solvent-free surface functionalization approach based on the chemical vapor deposition (CVD) method to establish an extremely thin yet uniform coating layer to improve foam performance. The PU foam was respectively functionalized using different monomers, i.e., perfluorodecyl acrylate (PFDA), 2,2,3,4,4,4-hexafluorobutyl acrylate (HFBA), and hexamethyldisiloxane (HMDSO), and the effect of deposition times (1, 5 and 10 min) on the properties of foam was investigated. The results showed that all the modified foams demonstrated a much higher water contact angle (i.e., greater hydrophobicity) and greater absorption capacities compared to the control PU foam. This is due to the presence of specific functional groups, e.g., fluorine (F) and silane (Si) in the modified PU foams. Of all, the PU/PHFBAi foam exhibited the highest absorption capacities, recording 66.68, 58.15, 53.70, and 58.38 g/g for chloroform, acetone, cyclohexane, and edible oil, respectively. These values were 39.19–119.31% higher than that of control foam. The promising performance of the PU/PHFBAi foam is due to the improved surface hydrophobicity attributed to the original perfluoroalkyl moieties of the HFBA monomer. The PU/PHFBAi foam also demonstrated a much more stable absorption performance compared to the control foam when both samples were reused for up to 10 cycles. This clearly indicates the positive impact of the proposed functionalization method in improving PU properties for oil absorption processes.

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

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4977
Author(s):  
Tomasz Ganicz ◽  
Krystyna Rózga-Wijas
Keyword(s):  
High Surface ◽  
Barrier Properties ◽  
Surface Hydrophobicity ◽  
Contact Angles ◽  
Recycling Process ◽  
Water Contact ◽  
Cellulosic Materials ◽  
Circulating Water ◽  
Hydrophobic Coating ◽  
Aqueous Mixture

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.

Surface Modification of Poly(lactic acid) (PLA) via Alkaline Hydrolysis Degradation

2014 ◽  
Vol 970 ◽  
pp. 324-327 ◽  
Author(s):  
Cho Yin Tham ◽  
Zuratul Ain Abdul Hamid ◽  
Zulkifli Ahmad ◽  
Hanafi Ismail
Keyword(s):  
Contact Angle ◽  
Lactic Acid ◽  
Surface Treatment ◽  
Alkaline Hydrolysis ◽  
Surface Hydrophobicity ◽  
Alkaline Treatment ◽  
Poly Lactic Acid ◽  
Surface Erosion ◽  
Water Contact ◽  
Surface Hydrophilicity

Surface hydrophobicity of poly (lactic acid) have raise the concerns of surface incompatibility of PLA to function as biomaterial. Thus, various approaches have been made to improve the surface hydrophilicity of PLA. In the present paper, PLA materials were surface modified by alkaline hydrolysis. The indication of the reduction in water contact angle value, from 65 ̊ to 50 ̊ and 15 ̊, in 0.01M and 1M alkaline concentration respectively, proven surface hydrophilicity of PLA film was improved. Further alkaline treatment after 24 hours shows not significant reduction in contact angle. Whereas, the erosion of film surfaces treated under 1M alkaline solution have been observed under polarized optical microscopy. Intrinsic viscosity measurement was also conducted to monitor the surface treatment process. As a whole, surface treatment was successful and sufficient when no further decreased in contact angle value, thus prevent extensive surface erosion.

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

Coatings ◽  
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.

scholarly journals AACVD Synthesis and Characterization of Iron and Copper Oxides Modified ZnO Structured Films

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 471 ◽  
Author(s):  
Martha Claros ◽  
Milena Setka ◽  
Yecid P. Jimenez ◽  
Stella Vallejos
Keyword(s):  
Contact Angle ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Contact Angles ◽  
Copper Oxides ◽  
Water Contact ◽  
X Ray ◽  
Hydrophobic Behavior

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.

scholarly journals One-Step Preparation of Durable Super-Hydrophobic MSR/SiO2 Coatings by Suspension Air Spraying

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 677 ◽  
Author(s):  
Zhengyong Huang ◽  
Wenjie Xu ◽  
Yu Wang ◽  
Haohuan Wang ◽  
Ruiqi Zhang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Adhesion Strength ◽  
Contact Angle Hysteresis ◽  
Surface Hardness ◽  
Hierarchical Structures ◽  
Hydrophobic Surface ◽  
Water Contact ◽  
Hydrophobic Coating ◽  
Mechanical Durability ◽  
One Step

In this study, we develop a facial one-step approach to prepare durable super-hydrophobic coatings on glass surfaces. The hydrophobic characteristics, corrosive liquid resistance, and mechanical durability of the super-hydrophobic surface are presented. The as-prepared super-hydrophobic surface exhibits a water contact angle (WCA) of 157.2° and contact angle hysteresis of 2.3°. Mico/nano hierarchical structures and elements of silicon and fluorine is observed on super-hydrophobic surfaces. The adhesion strength and hardness of the surface are determined to be 1st level and 4H, respectively. The coating is, thus, capable of maintaining super-hydrophobic state after sand grinding with a load of 200 g and wear distances of 700 mm. The rough surface retained after severe mechanical abrasion observed by atomic force microscope (AFM) microscopically proves the durable origin of the super-hydrophobic coating. Results demonstrate the feasibility of production of the durable super-hydrophobic coating via enhancing its adhesion strength and surface hardness.

scholarly journals Suppression of Hydrophobic Recovery in Photo-Initiated Chemical Vapor Deposition

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 534
Author(s):  
Alessio Aufoujal ◽  
Ulrich Legrand ◽  
Jean-Luc Meunier ◽  
Jason Robert Tavares
Keyword(s):  
Contact Angle ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Water Contact ◽  
Initiated Chemical Vapor Deposition ◽  
Hydrophobic Recovery ◽  
Topmost Layer ◽  
Nanometric Film ◽  
Polar Functional Groups

Photo-initiated chemical vapor deposition (PICVD) functionalizes carbon nanotube (CNT)-enhanced porous substrates with a highly polar polymeric nanometric film, rendering them super-hydrophilic. Despite its ability to generate fully wettable surfaces at low temperatures and atmospheric pressure, PICVD coatings normally undergo hydrophobic recovery. This is a process by which a percentage of oxygenated functional group diffuse/re-arrange from the top layer of the deposited film towards the bulk of the substrate, taking the induced hydrophilic property of the material with them. Thus, hydrophilicity decreases over time. To address this, a vertical chemical gradient (VCG) can be deposited onto the CNT-substrate. The VCG consists of a first, thicker highly cross-linked layer followed by a second, thinner highly functionalized layer. In this article, we show, through water contact angle and XPS measurements, that the increased cross-linking density of the first layer can reduce the mobility of polar functional groups, forcing them to remain at the topmost layer of the PICVD coating and to suppress hydrophobic recovery. We show that employing a bi-layer VCG suppresses hydrophobic recovery for five days and reduces its effect afterwards (contact angle stabilizes to 42 ± 1° instead of 125 ± 3°).

Synthesis by plasma-enhanced chemical-vapor deposition and characterization of siliconlike films with hydrophobic functionalities for improved long-term geometric stability of fiber-reinforced polymers

2008 ◽  
Vol 23 (4) ◽  
pp. 1042-1050 ◽  
Author(s):  
A. Cremona ◽  
E. Vassallo ◽  
A. Merlo ◽  
A. Srikantha Phani ◽  
L. Laguardia
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
High Strength ◽  
Scratch Resistance ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Water Contact ◽  
Fiber Failure

Amorphous siliconlike films with hydrophobic functionalities have been deposited by plasma-enhanced chemical-vapor deposition on carbon-fiber-reinforced polymer (CFRP) unidirectional laminates used for micromechanical applications where high strength-to-weight and high stiffness-to-weight ratios are required. To improve long-term geometrical stability in ultrahigh-precision machine structures, hydrophobic CFRP materials are desirable. Three layers have been grown with different plasma-process parameters from a mixture of hexamethyldisiloxane, O2, and Ar. Chemical composition, water contact angle, surface energy, morphology, and tribological properties have been evaluated to choose the one that best fulfills hydrophobicity, wear, and scratch resistance. Wear tests have also been carried out on CFRP laminates coated with a polyurethane layer to compare the wear performance of the above specimens with that of a conventional hydrophobic coating. Scanning electron microscope images show a very good adhesion of the films to the composite substrate because the failure of the film and of the substrate (such as fiber failure) take place simultaneously.

An investigation into the anti-icing properties of fabrics used for the outer layer of firefighter clothing

2018 ◽  
Vol 89 (8) ◽  
pp. 1500-1511 ◽  
Author(s):  
Lun Han ◽  
Xiaoming Zhao ◽  
Jannette Eveline Kidalla
Keyword(s):  
Outer Layer ◽  
Photoelectron Spectroscopy ◽  
Smooth Surface ◽  
Hydrophobic Surface ◽  
Hydrophobic Property ◽  
Water Contact ◽  
Hydrophobic Coating ◽  
Before And After ◽  
Coating Method ◽  
Fabric Surface

The anti-icing properties of fabrics can be considered as involving two parts, the super-hydrophobic property and the ease of ice removal property. In this study, a super-hydrophobic surface was built on to the outer layer of firefighter clothing using nano-silica, C13H13F17O3Si, C19H42O3Si and PU-2540 using a coating method. This coating stops water drops from staying on the fabric surface easily. At the same time, an ultra-smooth surface was built on to the super-hydrophobic surface already created on the fabric using perfluoropolyethers (PFPE) oil by a dipping method, which adds an ice removal function to the fabrics. The anti-icing properties of the samples prepared in the research described in this paper have been investigated using field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), ease of ice removal property tests and static water contact angle analysis. At the same time, the thermal protective performance (TPP) of the samples, before and after super-hydrophobic treatment, was studied by a TPP tester. Results show that the super-hydrophobic coating with an ultra-smooth surface can significantly increase the anti-icing properties of the fabrics used for the outer layer of firefighter clothing. C13H13F17O3Si and C19H42O3Si can improve the hydrophobic properties of the coating. The anti-icing coating in this paper can increase the TPP of the fabrics.

scholarly journals Transparent superhydrophobic PTFE films via one-step aerosol assisted chemical vapor deposition

RSC Advances ◽  
2017 ◽  
Vol 7 (47) ◽  
pp. 29275-29283 ◽  
Author(s):  
Aoyun Zhuang ◽  
Ruijin Liao ◽  
Sebastian C. Dixon ◽  
Yao Lu ◽  
Sanjayan Sathasivam ◽  
...  
Keyword(s):  
Contact Angle ◽  
Chemical Vapor Deposition ◽  
Water Contact Angle ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Sliding Angle ◽  
Water Contact ◽  
Visible Transmittance ◽  
One Step

Hierarchical micro/nano-structured transparent superhydrophobic polytetrafluoroethylene films with water contact angle 168°, water sliding angle <1° and visible transmittance >90% were prepared on glass via aerosol-assisted chemical vapor deposition.

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