Self‐Generation of Surface Roughness by Low‐Surface‐Energy Alkyl Chains for Highly Stable Superhydrophobic/Superoleophilic MOFs with Multiple Functionalities

AbstractAdhesion between bodies is strongly influenced by surface roughness. In this note, we try to clarify how the statistical properties of the contacting surfaces affect the adhesion under the assumption of long-range adhesive interactions.Specifically, we show that the adhesive interactions are influenced only by the roughness amplitude hrms, while the rms surface gradient h0rmsonly affects the non-adhesive contact force. This is a remarkable result if one takes into account the intrinsic difficulty in defining $h_{\mathrm{rms}}^{^{\prime }}.$Results are also corroborated by a comparison with self-consistent numerical calculations.

Download Full-text

Superamphiphobic surfaces

Chemical Society Reviews ◽

10.1039/c3cs60415b ◽

2014 ◽

Vol 43 (8) ◽

pp. 2784-2798 ◽

Cited By ~ 348

Author(s):

Zonglin Chu ◽

Stefan Seeger

Keyword(s):

Surface Roughness ◽

Surface Modification ◽

Surface Energy ◽

Energy Materials ◽

Low Surface Energy

Progress in superamphiphobic surfaces, including the characterization, different techniques towards the fabrication of surface roughness and surface modification with low-surface-energy materials as well as their applications, is reviewed.

Download Full-text

Self-Stratifying Particulate Coating for Robust Superhydrophobic and Latex-Repellent Surface

Journal of Environmental Treatment Techniques ◽

10.47277/jeet/8(3)1111 ◽

2020 ◽

Vol 8 (3) ◽

pp. 1111-1117

Keyword(s):

Surface Roughness ◽

Surface Energy ◽

Film Surface ◽

Contact Angles ◽

Polymer Binder ◽

Drying Temperature ◽

Low Surface Energy ◽

Mechanical Durability ◽

Film Substrate ◽

Convection Dominated

A technique for preparing superhydrophobic and natural latex-repellent surface requires at least two fabrication components: surface roughness, and surface layer with low free energy. Here, multiscale surface roughness in micro-/nanoscales with low surface energy can be simultaneously achieved through the deposition of fluoroalkyl-functionalized silica aggregates. However, the mechanical durability of such film remains problematic. Therefore, third component such as polymer binder was incorporated carefully to improve adhesion between film-substrate interface without deteriorating surface roughness and surface energy. In this work, we employed self-stratifying coating technique to induce vertical phase separation between particles and polymer during film drying, such that the silica aggregates densely accumulated on the top surface, while polymer binder concentrated near the film bottom. The governing transports during film stratification process involve diffusion and convection driven by evaporation. Thus, this research focused on the effect of drying temperature and evaporation rate on the anti-wetting performance of the coating. The results showed that the liquid-repellent properties of the surface improve with increasing drying temperature, indicating the convection-dominated transport that induced substantial particle trap at the film surface. With polymer binder added, the coatings still showed decent superhydrophobic and natural latex-repellent properties with maximum contact angles 166.4°±0.6° and 157.5°±0.5°, as well as minimum sliding angles 2.7°±0.3° and 2.9°±0.2° for water and natural latex respectively. Also, AFM result revealed that significant surface roughness of 581 ± 18 nm was still achievable even at high blending mass ratio of polymer binder up to half of the silica weight.

Download Full-text

Effect of Etching and Modification on the Hydrophobic Angle of Epoxy/Poss Nanomaterials

Journal of Nanoelectronics and Optoelectronics ◽

10.1166/jno.2020.2899 ◽

2020 ◽

Vol 15 (12) ◽

pp. 1502-1507

Author(s):

Yanhong Fang ◽

Ping Wang ◽

Lifang Sun ◽

Linhong Wang

Keyword(s):

Surface Roughness ◽

Contact Angle ◽

Hydrochloric Acid ◽

Surface Energy ◽

Stearic Acid ◽

Acid Etching ◽

Energy Materials ◽

Nano Structure ◽

Low Surface Energy ◽

Long Time

In this study, simple and feasible methods are used to increase the hydrophobicity of EP-POSS, that is, etching with concentrated hydrochloric acid and concentrated ammonia water, followed by modification with polytetrafluoroethylene and stearic acid. The principle of the study is to increase the hydrophobic angle of EP-POSS by immersion in concentrated hydrochloric acid and concentrated ammonia for a sufficiently long time, followed by modification with low-surface-energy materials, i.e., polytetrafluoroethylene and stearic acid. The contact angle of EP-POSS increased from 100° to 133° after immersing in 3 mol/L hydrochloric acid for 12 min. Compared to hydrochloric acid, the surface roughness and contact angel were not changed significantly by immersing in concentrated ammonia for 4 hours. The contact angle was not changed obviously after immersing in 0.1 mol/L polytetrafluoroethylene for 24 h, and only changed from 135° to 136° when immersed in 0.1 mol/L stearic acid. It shows that PTFE and stearic acid hasn?t effectively grafted to the surface of EP-POSS, and has no effect to the micro-nano structure of EP-POSS. According to the experimental results, hydrochloric acid etching is the proper way to enhance EP-POSS contact angel. According to further investigates, it can be determined that treating EP-POSS at 40 °C for 12 min with 3 mol/L hydrochloric acid can significantly improve its hydrophobicity, thus, the hydrophobic performance of EP-POSS is considerably improved.

Download Full-text

A new method for quantifying the blocking of coated paperboard

TAPPI Journal ◽

10.32964/tj9.5.29 ◽

2010 ◽

Vol 9 (5) ◽

pp. 29-35 ◽

Cited By ~ 2

Author(s):

PAULINE SKILLINGTON ◽

YOLANDE R. SCHOEMAN ◽

VALESKA CLOETE ◽

PATRICE C. HARTMANN

Keyword(s):

Surface Roughness ◽

Fatty Acid ◽

Surface Energy ◽

Film Thickness ◽

External Factors ◽

Additive Concentration ◽

Pressure Surface ◽

Fatty Acid Amides ◽

Coated Surfaces ◽

Definite Period

Blocking is undesired adhesion between two surfaces when subjected to pressure and temperature constraints. Blocking between two coated paperboards in contact with each other may be caused by inter-diffusion, adsorption, or electrostatic forces occurring between the respective coating surfaces. These interactions are influenced by factors such as the temperature, pressure, surface roughness, and surface energy. Blocking potentially can be reduced by adjusting these factors, or by using antiblocking additives such as talc, amorphous silica, fatty acid amides, or polymeric waxes. We developed a method of quantifying blocking using a rheometer. Coated surfaces were put in contact with each other with controlled pressure and temperature for a definite period. We then measured the work necessary to pull the two surfaces apart. This was a reproducible way to accurately quantify blocking. The method was applied to determine the effect external factors have on the blocking tendency of coated paperboards, i.e., antiblocking additive concentration, film thickness, temperature, and humidity.

Download Full-text

Cytocompatibility of Carbon Nanofiber Materials for Neural Applications

MRS Proceedings ◽

10.1557/proc-774-o7.35 ◽

2003 ◽

Vol 774 ◽

Author(s):

Janice L. McKenzie ◽

Michael C. Waid ◽

Riyi Shi ◽

Thomas J. Webster

Keyword(s):

Carbon Fiber ◽

Surface Energy ◽

Carbon Nanofibers ◽

Carbon Fibers ◽

Carbon Nanofiber ◽

Fiber Composite ◽

Scar Tissue ◽

Pc 12 Cells ◽

Low Surface Energy ◽

Poly Carbonate

AbstractSince the cytocompatibility of carbon nanofibers with respect to neural applications remains largely uninvestigated, the objective of the present in vitro study was to determine cytocompatibility properties of formulations containing carbon nanofibers. Carbon fiber substrates were prepared from four different types of carbon fibers, two with nanoscale diameters (nanophase, or less than or equal to 100 nm) and two with conventional diameters (or greater than 200 nm). Within these two categories, both a high and a low surface energy fiber were investigated and tested. Astrocytes (glial scar tissue-forming cells) and pheochromocytoma cells (PC-12; neuronal-like cells) were seeded separately onto the substrates. Results provided the first evidence that astrocytes preferentially adhered on the carbon fiber that had the largest diameter and the lowest surface energy. PC-12 cells exhibited the most neurites on the carbon fiber with nanodimensions and low surface energy. These results may indicate that PC-12 cells prefer nanoscale carbon fibers while astrocytes prefer conventional scale fibers. A composite was formed from poly-carbonate urethane and the 60 nm carbon fiber. Composite substrates were thus formed using different weight percentages of this fiber in the polymer matrix. Increased astrocyte adherence and PC-12 neurite density corresponded to decreasing amounts of the carbon nanofibers in the poly-carbonate urethane matrices. Controlling carbon fiber diameter may be an approach for increasing implant contact with neurons and decreasing scar tissue formation.

Download Full-text