Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Water-Repellent Nanotextures Found to Have Excellent Anti-Fogging Abilities: Cone-shaped nanotextures could prevent fog condensation on surfaces in humid environments, including for power generation and transportation applications

The series of optical microscope images (a) show the patterns formed by the condensation of water from a supersaturated atmosphere on surfaces textured with nanocylinders (top row) and nanocones (bottom row) throughout a 45-minute period. Both textures start out covered with microdroplets, but the cylindrical texture shows large droplets forming over time that stick to the surface. In contrast, the conical texture resists dew formation because the water droplets are so lightly adhered to the surface that, when two drops join together (b, top), they gain enough energy to spontaneously jump off the surface (b, bottom).
The series of optical microscope images (a) show the patterns formed by the condensation of water from a supersaturated atmosphere on surfaces textured with nanocylinders (top row) and nanocones (bottom row) throughout a 45-minute period. Both textures start out covered with microdroplets, but the cylindrical texture shows large droplets forming over time that stick to the surface. In contrast, the conical texture resists dew formation because the water droplets are so lightly adhered to the surface that, when two drops join together (b, top), they gain enough energy to spontaneously jump off the surface (b, bottom).

Abstract:
Some insect bodies have evolved the abilities to repel water and oil, adhere to different surfaces, and eliminate light reflections. Scientists have been studying the physical mechanisms underlying these remarkable properties found in nature and mimicking them to design materials for use in everyday life.

Water-Repellent Nanotextures Found to Have Excellent Anti-Fogging Abilities: Cone-shaped nanotextures could prevent fog condensation on surfaces in humid environments, including for power generation and transportation applications

Upton, NY | Posted on March 2nd, 2017

Several years ago, scientists at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory developed a nanoscale surface-texturing method for imparting complete water repellency to materials-a property inspired by insect exoskeletons that have tiny hairs designed to repel water by trapping air. Their method leverages the ability of materials called block copolymers (chains of two distinct molecules linked together) to self-assemble into ordered patterns with dimensions measuring only tens of nanometers in size. The scientists used these self-assembled patterns to create nanoscale textures in a variety of inorganic materials, including silicon, glass, and some plastics. Initially, they studied how changing the shape of the textures from cylindrical to conical impacted materials' ability to repel water. Cone-shaped nanotextures proved much better at forcing water droplets to roll off, carrying dirt particles away and leaving surfaces completely dry.

Now, working with colleagues in France-from ESPCI Paris Tech, École Polytechnique, and the Thales Group-they have further shown that the optimized nanotextures have excellent anti-fogging abilities, as described in a paper published online in the Feb. 27 issue of Nature Materials. Led by David Quéré of ESPCI and École Polytechnique, the research provides a fundamental understanding that may inform new designs for condensing coils of steam turbine power generators, car and aircraft windshields, and other materials prone to fogging.

"Many textured materials can repel water, with millimeter-size water drops bouncing off their surfaces, but many of these surfaces fail when exposed to foggy or humid conditions," said Charles Black, director of Brookhaven Lab's Center for Functional Nanomaterials [ https://www.bnl.gov/cfn/ ] (CFN), the DOE Office of Science User Facility where Black and former physicist Antonio Checco of Brookhaven's Condensed Matter Physics and Materials Science Department and former CFN postdoctoral research associate Atikur Rahman fabricated the nanotextures.

Fog forms when warm, moist air hits a cooler surface (such as a window or windshield) and forms water droplets-a process called condensation. When water droplets are similar in size to the structural features of a textured hydrophobic ("water hating") surface, they can get inside and grow within the texture, instead of remaining on top. Once the texture fills up, water landing on the material gets stuck, resulting in the appearance of fog.

Scientists have previously observed that the wings of cicadas, which are covered by nanosized cone-shaped textures, have the ability to repel fog by causing water droplets to spontaneously jump off their surface-a phenomenon caused by the efficient conversion of surface energy to kinetic energy when two droplets combine. Motivated by this example from nature, the team investigated how reducing texture size and changing texture shape impacts the anti-fogging ability of a model surface.

To simulate fogging conditions, the scientists heated water and measured the adhesion force as warm water droplets cooled upon contacting the nanotextured surfaces. These measurements revealed that droplet adhesion was significantly affected by the type of surface nanotexture, with warm drops strongly sticking to those with large textures and hardly sticking at all to surfaces with the smallest ones.

"Textures with the smallest feature sizes and the appropriate shape-in this case, conical-resist fogging because condensing water droplets are too big to penetrate the texture. The droplets remain on top, essentially floating on the cushion of air trapped beneath," said Black.

The scientists next used an optical microscope connected to a high-resolution video camera to view droplet condensation on different textures during dew formation, when atmospheric moisture condenses faster than it evaporates. While all textures are initially covered by large numbers of microdroplets, over time textures with a cylindrical shape become covered in water, while the ones with a conical shape spontaneously dry themselves. Conical-shaped textures resist dew formation because the water droplets are so lightly adhered to the surface that when two drops join together, they gain enough energy to spontaneously jump off the surface, similar to the mechanism observed in cicada wings.

"This work represents the excellent, multiplicative power of DOE user facilities. In this case, CFN's initial collaboration with a user from one of Brookhaven's departments led to a new international connection with different users, who carried the study of hydrophobic surfaces in new directions," said Black.

This research was supported by the DOE Office of Science, the French Ministry of Defense procurement agency, and the Thales Group.

####

About Brookhaven National Laboratory
Brookhaven National Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

For more information, please click here

Contacts:
Ariana Tantillo
(631) 344-2347,

or
Peter Genzer
(631) 344-3174

Copyright © Brookhaven National Laboratory

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Scientific paper: "Antifogging abilities of model nanotextures":

Related News Press

News and information

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Videos/Movies

New X-ray imaging technique to study the transient phases of quantum materials December 29th, 2022

Solvent study solves solar cell durability puzzle: Rice-led project could make perovskite cells ready for prime time September 23rd, 2022

Scientists prepare for the world’s smallest race: Nanocar Race II March 18th, 2022

Visualizing the invisible: New fluorescent DNA label reveals nanoscopic cancer features March 4th, 2022

Govt.-Legislation/Regulation/Funding/Policy

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

Institute for Nanoscience hosts annual proposal planning meeting May 16th, 2025

Rice researchers harness gravity to create low-cost device for rapid cell analysis February 28th, 2025

Possible Futures

Ben-Gurion University of the Negev researchers several steps closer to harnessing patient's own T-cells to fight off cancer June 6th, 2025

Researchers unveil a groundbreaking clay-based solution to capture carbon dioxide and combat climate change June 6th, 2025

Cambridge chemists discover simple way to build bigger molecules – one carbon at a time June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Discoveries

Researchers unveil a groundbreaking clay-based solution to capture carbon dioxide and combat climate change June 6th, 2025

Cambridge chemists discover simple way to build bigger molecules – one carbon at a time June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Materials/Metamaterials/Magnetoresistance

Researchers unveil a groundbreaking clay-based solution to capture carbon dioxide and combat climate change June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Institute for Nanoscience hosts annual proposal planning meeting May 16th, 2025

Superconductors: Amazingly orderly disorder: A surprising effect was discovered through a collaborative effort by researchers from TU Wien and institutions in Croatia, France, Poland, Singapore, Switzerland, and the US during the investigation of a special material: the atoms are May 14th, 2025

Announcements

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters

Cambridge chemists discover simple way to build bigger molecules – one carbon at a time June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Energy

Portable Raman analyzer detects hydrogen leaks from a distance: Device senses tiny concentration changes of hydrogen in ambient air, offering a dependable way to detect and locate leaks in pipelines and industrial systems April 25th, 2025

KAIST researchers introduce new and improved, next-generation perovskite solar cell​ November 8th, 2024

Unveiling the power of hot carriers in plasmonic nanostructures August 16th, 2024

Groundbreaking precision in single-molecule optoelectronics August 16th, 2024

Automotive/Transportation

Portable Raman analyzer detects hydrogen leaks from a distance: Device senses tiny concentration changes of hydrogen in ambient air, offering a dependable way to detect and locate leaks in pipelines and industrial systems April 25th, 2025

Leading the charge to better batteries February 28th, 2025

Researchers are cracking the code on solid-state batteries: Using a combination of advanced imagery and ultra-thin coatings, University of Missouri researchers are working to revolutionize solid-state battery performance February 28th, 2025

Giving batteries a longer life with the Advanced Photon Source: New research uncovers a hydrogen-centered mechanism that triggers degradation in the lithium-ion batteries that power electric vehicles September 13th, 2024

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project