scholarly journals Effect of Structure Hierarchy for Superhydrophobic Polymer Surfaces Studied by Droplet Evaporation

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 831 ◽  
Author(s):  
Nastasia Okulova ◽  
Peter Johansen ◽  
Lars Christensen ◽  
Rafael Taboryski
Keyword(s):  
Hierarchical Structures ◽  
Droplet Evaporation ◽  
Contact Angles ◽  
Surface Structures ◽  
Water Contact ◽  
Surface Design ◽  
Force Microscopy ◽  
Extrusion Coating ◽  
Coating Method ◽  
Micro Pillars

Super-hydrophobic natural surfaces usually have multiple levels of structure hierarchy. Here, we report on the effect of surface structure hierarchy for droplet evaporation. The two-level hierarchical structures studied comprise micro-pillars superimposed with nanograss. The surface design is fully scalable as structures used in this study are replicated in polypropylene by a fast roll-to-roll extrusion coating method, which allows effective thermoforming of the surface structures on flexible substrates. As one of the main results, we show that the hierarchical structures can withstand pinning of sessile droplets and remain super-hydrophobic for a longer time than their non-hierarchical counterparts. The effect is documented by recording the water contact angles of sessile droplets during their evaporation from the surfaces. The surface morphology is mapped by atomic force microscopy (AFM) and used together with the theory of Miwa et al. to estimate the degree of water impregnation into the surface structures. Finally, the different behavior during the droplet evaporation is discussed in the light of the obtained water impregnation levels.

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

2017 ◽  
Vol 95 (5) ◽  
pp. 605-611 ◽  
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.

Fabrication and Characterization of Ultra Water Repellent Surfaces on Aluminum Alloy Substrate

2016 ◽  
Vol 705 ◽  
pp. 278-282
Author(s):  
Ri Han Chi ◽  
Yue Fei Yu ◽  
Zhi Jia Yu ◽  
Guo Zhu Kuang
Keyword(s):  
Aluminum Alloy ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Water Repellent ◽  
Water Contact ◽  
Hierarchical Roughness ◽  
Silane Coating ◽  
Coating Method ◽  
Sinusoidal Flow

The fabrication of metallic ultra water repellent surfaces is of great significance to many industrial and scientific areas. Ultra water repellent surfaces on aluminum alloy substrates were fabricated with acidic etching and fluoroalkyl silane coating method. The prepared surfaces exhibit good water repellent behaviors with water contact angles (WCA) larger than 150° and contact angle hysteresis (CAH) about 5°. The resultant surfaces were examined using scanning electron microscope (SEM). The results show that a kind of hierarchical roughness in micro-nanoscale is formed, which plays a key role for the fabrication of ultra water repellent surfaces. Fancy phenomena such as "chair-shaped flow", "flow orientation" and "sinusoidal flow" were observed when water flowed in a rectangular conduit constructed with one ultra water repellent wall and one super hydrophilic wall on the opposite side. The observations reveal some characteristics of water flow in ultra water repellent conduits.

Yeast Cells Immobilization in Microfluidic Channels Based on a Self-Polymerized Nano-Film of Poly(Dopamine)

2015 ◽  
Vol 645-646 ◽  
pp. 1357-1362
Author(s):  
Xing Chen ◽  
Lu Lu Zhang ◽  
Jian Hai Sun ◽  
Hui Li ◽  
Da Fu Cui
Keyword(s):  
Cell Immobilization ◽  
Contact Angles ◽  
Yeast Cells ◽  
Microfluidic Channels ◽  
Universal Method ◽  
Label Free ◽  
Suspension Cells ◽  
Water Contact ◽  
Force Microscopy ◽  
Immobilized Yeast Cells

In this paper, an effective, simple and universal method for cell immobilization was developed. A self-polymerization nanofilm of poly (dopamine) was used to fix yeast cells in microfluidic channels. The surface morphology of the poly (dopamine) film was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. Water contact angles (WCA) was also used to characterize the surface property of the poly (dopamine) nanofilm. The WCA on the PDMS substrates rapidly decreased from 105° to 59.8° with an increase in poly (dopamine) coating time. The interfacial process of dopamine self-polymerization and the cell immobilization were measured in a label-free and real-time mode by a surface plasmon resonance (SPR) instrument. Finally the immobilized yeast cells were observed by using a light microscope. From the experimental results, the yeast cells can be easily immobilized on the microfluidic channels modified with the nanofilm of poly (dopamine), which will hold great potential for the immobilization, detection and further analysis of other suspension cells, such as blood cells.

scholarly journals Dip-Coating Approach to Fabricate Durable PDMS/STA/SiO2 Superhydrophobic Polyester Fabrics

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 326
Author(s):  
Xiaoli Liu ◽  
Youcai Gu ◽  
Tengfei Mi ◽  
Xiaomei Wang ◽  
Xu Zhang
Keyword(s):  
Contact Angle ◽  
Textile Industry ◽  
Dip Coating ◽  
Water Contact ◽  
Force Microscopy ◽  
Superhydrophobic Coatings ◽  
Atomic Force ◽  
High Durability ◽  
Coating Method ◽  
Dip Coating Method

The facile, simple, highly efficient, and fluorine-free fabrication of superhydrophobic surfaces on fabrics with high durability has attracted considerable attention because of its urgent practical application. The simple dip-coating method was adopted to make a stable and durable polydimethylsiloxane/stearic acid/silica (PDMS/STA/SiO2) superhydrophobic fabric. The fabric’s surface morphology, roughness, and composition were analyzed by scanning electron microscopy, atomic force microscopy, and Fourier transform infrared spectroscopy, respectively. The PDMS/STA/SiO2-coated fabric: demonstrated strong superhydrophobicity (a water contact angle (WCA) of around 163°), efficiently repelled different liquids (milk, coffee, orange juice, Coca-Cola, and 1 M of HCl and NaOH) with a contact angle above 155°, had excellent self-cleaning performance, and retained superhydrophobicity with a WCA greater than 150° after 72 h of ultraviolet irradiation and 700 cycles of mechanical abrasion. The PDMS/STA/SiO2 coating had few influences on the color fastness of the fabric. Superhydrophobic coatings are expected to be practically applied in the textile industry.

scholarly journals Bioinspired Polyethersulfone Membrane Design via Blending with Functional Polyurethane

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Mei Han ◽  
Qiang Liu ◽  
Baihai Su ◽  
Shudong Sun ◽  
Changsheng Zhao
Keyword(s):  
Blood Compatibility ◽  
Composite Membranes ◽  
Contact Angles ◽  
Vinyl Pyrrolidone ◽  
Water Contact ◽  
Cross Sectional ◽  
Surface Design ◽  
Reversible Addition ◽  
Poly Vinyl Pyrrolidone ◽  
Chain Transfer Polymerization

Polyurethanes (PUs) are currently considered to be biocompatible materials but limited by a low resistance to thrombus. We therefore design a heparin-like PU (HLPU) to modify polyethersulfone (PES) membranes approaching integrated antifouling and antithrombotic properties by bioinspiration of heparin structure. Poly(vinyl pyrrolidone)-HLPU (PVP-HLPU) was synthesized via reversible addition-fragmentation chain transfer polymerization of VP using PU as a macroinitiator and then sulfonated by concentrated H2SO4. FTIR and NMR results demonstrated the successful synthesis of PVP-HLPU. By incorporation of PVP-HLPU, the cross-sectional structure of PES composite membranes altered from finger-like structure to sponge-like structure resulting in tunable permeability. The increased hydrophilicity verified by water contact angles benefited both the permeability and antifouling property. As a consequence, the composite membranes showed good blood compatibility, including decreased protein adsorption, suppressed platelet adhesion, lowered thrombin-antithrombin III generation, reduced complement activation, and prolonged clotting times. Interestingly, the PVP-capped HLPU showed better blood compatibility compared to polyethyleneglycol-capped and citric acid-capped HLPUs. The results demonstrated the enhanced antifouling and antithrombotic properties of PES hemodialysis membranes by the introduction of functional HLPUs. Also, the proposed method may forward the fabrication of hemocompatible membranes via bioinspired surface design.

scholarly journals Screening the Optimal Patterned Surfaces Consisting of Cell Morphology Mimicking Micro-pillars and Nanotube Arrays for the Design of Titanium Implants

2021 ◽  
Vol 18 (2) ◽  
pp. 361-374
Author(s):  
Ping Zhou ◽  
Hongjiao Li ◽  
Feifei Mao ◽  
Hongxin Huang ◽  
Siqi Long ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cell Morphology ◽  
Contact Angles ◽  
Titanium Implants ◽  
Nanotube Arrays ◽  
Water Contact ◽  
Contact Printing ◽  
Nano Scale ◽  
Bionic Structure ◽  
Micro Pillars

AbstractMicron/nano scale topographic modification has been a significant focus of interest in current titanium (Ti) surface design. However, the influence of micron/nano structured surface on cell or bacterium behavior on the Ti implant has rarely been systematically evaluated. Moreover, except for popular microgrooves, little work has been carried out on the reaction of cells to the bionic structure. In this study, several micro-pillars mimicking cell morphology were prepared on Ti surfaces by lithography and contact printing (ICP) method, and they were further decorated with nanotube arrays by anodization technology. These surface modifications remarkablly increased the surface roughness of pristine Ti surface from 91.17 nm ± 5.57 nm to be more than 1000 nm, and reduced their water contact angles from 68.3° ± 0.7° to be 16.9° ± 2.4°. Then, the effects of these hierarchical micron/nano scale patterns on the behaviors of MG63 osteoblasts, L929 fibroblasts, SCC epithelial cells and P. gingivalis were studied, aiming to evaluate their performance in osseointegration, gingival epithelial sealing and antibacterial ability. Through an innovative scoring strategy, our findings showed that square micro-pillars with 6 µm width and 2 µm height combined with 85 nm diameter nanotubes was suitable for implant neck design, while square micro-pillars with 3 µm width and 3.6 µm height combined with 55 nm diameter nanotubes was the best for implant body design. Our study reveals the synergistic effect of the hierarchical micron/nano scale patterns on MG63 osteoblasts, L929 fibroblasts, SCC epithelial cells and P. gingivalis functions. It provides insight into the design of biomedical implant surfaces.

scholarly journals Large-Beam Picosecond Interference Patterning of Metallic Substrates

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4676
Author(s):  
Petr Hauschwitz ◽  
Dominika Jochcová ◽  
Radhakrishnan Jagdheesh ◽  
Martin Cimrman ◽  
Jan Brajer ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser System ◽  
Hierarchical Structures ◽  
High Energy ◽  
Contact Angles ◽  
Surface Structures ◽  
Laser Source ◽  
Metallic Substrates ◽  
And Tungsten

In this paper, we introduce a method to efficiently use a high-energy pulsed 1.7 ps HiLASE Perla laser system for two beam interference patterning. The newly developed method of large-beam interference patterning permits the production of micro and sub-micron sized features on a treated surface with increased processing throughputs by enlarging the interference area. The limits for beam enlarging are explained and calculated for the used laser source. The formation of a variety of surface micro and nanostructures and their combinations are reported on stainless steel, invar, and tungsten with the maximum fabrication speed of 206 cm2/min. The wettability of selected hierarchical structures combining interference patterns with 2.6 µm periodicity and the nanoscale surface structures on top were analyzed showing superhydrophobic behavior with contact angles of 164°, 156°, and 150° in the case of stainless steel, invar, and tungsten, respectively.

Functionalization of technical textile tapes

2018 ◽  
Vol 2 (89) ◽  
pp. 72-84
Author(s):  
W. Urbaniak-Domagała ◽  
E. Kobierska
Keyword(s):  
Hydrophobic Effect ◽  
Hierarchical Structures ◽  
High Water ◽  
Contact Angles ◽  
Slow Increase ◽  
Water Contact ◽  
Reduced Pressure ◽  
Dry Process ◽  
Hydrophobic Barrier ◽  
Fabric Surface

Purpose: The aim of the study was to deposit a hydrophobic barrier coating on technical tapes in order to protect them from water and to test and assess the obtained products. Design/methodology/approach: The coatings were deposited on elastic, textile substrates using PACVD of hexamethyldisiloxane vapours with an RF commercial plasma system under reduced pressure. Findings: The coatings increased the hydrophobicity of the technical tapes, which was confirmed by high water contact angles and reduced water sorption by the tape. The polymerization of the monomer vapour plasma was achieved without carrier gas. With a relatively slow increase in the deposition, rough coatings were obtained on a submicroscopic level, as opposed to the commonly produced smooth ppHMDSO coatings. This rough character enhanced the hydrophobicity of the surface according to the Wetzel or Cassie models. The modification processes did not significantly affect the basic mechanical properties of the tapes, such as Young’s modulus and tensile strength. The ppHMDSO coatings are resistant to aging and mechanical wear and retain their hydrophobic barrier properties. Research limitations/implications: The quantitative assessment of the wettability of a substrate with a rough surface is difficult and often ambiguous. This element of physicochemical metrology is wide open for innovation. Practical implications: The use of this plasma technique to make textile barrier products shows several merits, such as an economically justifiable, pro-ecological and dry process. The hydrophobicity of the textile substrates can also be obtained using other monomers. Originality/value: The formation of local hierarchical structures on the top layer of the fabric surface enhance the hydrophobic effect.

scholarly journals Cu∥-loaded polydopamine coatings with in situ nitric oxide generation function for improved hemocompatibility

2020 ◽  
Vol 7 (2) ◽  
pp. 153-160
Author(s):  
Lei Zhou ◽  
Xin Li ◽  
Kebing Wang ◽  
Fangyu Shen ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Contact Angles ◽  
Blood System ◽  
Signal Molecule ◽  
Water Contact ◽  
No Donor ◽  
Contact Materials ◽  
Force Microscopy ◽  
Composition And Structure ◽  
Pathological Environment

Abstract NO is the earliest discovered gas signal molecule which is produced by normal healthy endothelial cells, and it has many functions, such as maintaining cardiovascular homeostasis, regulating vasodilation, inhibiting intimal hyperplasia and preventing atherosclerosis in the blood system. Insufficient NO release is often observed in the pathological environment, for instance atherosclerosis. It was discovered that NO could be released from the human endogenous NO donor by many compounds, and these methods can be used for the treatment of certain diseases in the blood system. In this work, a series of copper-loaded polydopamine (PDA) coatings were produced through self-polymerization time for 24, 48 and 72 h. The chemical composition and structure, coating thickness and hydrophilicity of the different copper-loaded PDA coatings surfaces were characterized by phenol hydroxyl quantitative, X-ray photoelectron spectroscopy, ellipsometry atomic force microscopy and water contact angles. The results indicate that the thickness and the surface phenolic hydroxyl density of the PDA coatings increased with the polymerization time.This copper-loaded coating has glutathione peroxidase-like activity, and it has the capability of catalyzing NO releasing from GSNO. The surface of the coating showed desirable hemocompatibility, the adhesion and activation of platelets were inhibited on the copper-loaded coatings. At the same time, the formation of the thrombosis was also suppressed. These copper-loaded PDA coatings could provide a promising platform for the development of blood contact materials.

scholarly journals Durable and Superhydrophobic Aluminium Alloy with Microscale Hierarchical Structures and Anti-Drag Function Inspired by Diving Bell Spider

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1146
Author(s):  
You Chen ◽  
Zijing Quan ◽  
Yuhan Sun ◽  
Deqiang Chi ◽  
Delei Liu ◽  
...  
Keyword(s):  
Aluminium Alloy ◽  
Hierarchical Structures ◽  
Strong Acid ◽  
Contact Angles ◽  
Hierarchical Architecture ◽  
Viscous Drag ◽  
Microfluidic Chips ◽  
Coating Materials ◽  
Water Contact ◽  
Paint Systems

Coating materials with special surface wettability are widely applied in marine paint systems used in the naval industry to reduce the corrosion and viscous drag of seawater. However, traditional coatings are inefficient and limited, either by poor durability or insufficient anti-drag capacity. Here, inspired by the diving bell spider, a bionic superhydrophobic coating with multiscale hierarchical architecture was successfully prepared on the surface of aluminium alloy. It possesses excellent mechanical abrasion durability, chemical durability, and low adhesion. Remarkably, the water contact angles could remain over 150.9° after more than 15 abrasion cycles or strong acid/alkali conditions. In addition, the impacting water droplet lifted off the surface of bionic superhydrophobic aluminium alloy (BSAA) within 13 ms, illustrating an excellent low adhesion property. In fact, when the BSAA is immersed in water, it could absorb bubbles and form a gas membrane. The existence of the gas membrane could prevent water and anaerobic organisms from contacting and even corroding the BSAA. Meanwhile, the gas membrane acts as a lubricant and significantly deceases friction at the solid–liquid interface, reducing the drag for BSAA. The BSAA proposed in this work has broad application prospects, such as medical devices, microfluidic chips, gas separation and collection in water.

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