Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Glass matters: UCSB researchers find that the chemical topology of silica can influence the effectiveness of many chemical processes that use it

silica in test tube
silica in test tube

Abstract:
Better known as glass, silica is a versatile material used in myriad industrial processes, from catalysis and filtration, to chromatography and nanofabrication. Yet despite its ubiquity in labs and cleanrooms, surprisingly little is known about silica's surface interactions with water at a molecular level.

Glass matters: UCSB researchers find that the chemical topology of silica can influence the effectiveness of many chemical processes that use it

Santa Barbara, CA | Posted on March 14th, 2018

"The way water interacts with a surface affects many processes," said Songi Han, a UC Santa Barbara professor of chemistry and author on a recent paper in the Proceedings of the National Academy of Sciences. In many cases, she explained, scientists and engineers intuit the potential interactions between silica and water and design equipment, experiments and processes based on empirical evidence. But a mechanistic understanding of how the chemical topology of silica surfaces alter the structure of water at the surface could lead to a rationale design of these processes.

For many people, glass is glass, and brings to mind the clear, hard, smooth, homogenous-looking material that we use for windows or tableware. However, on a deeper level what we call "glass" is actually a more complex material that can contain different chemical properties with wide-ranging distributions.

"Glass is a material we're all familiar with, but what many people probably don't know is that it is what we would call a chemically heterogenous surface," said graduate student researcher Alex Schrader, lead author of the PNAS paper.

There are two different types of chemical groups that comprise glass surfaces, he said: silanol (SiOH) groups that are generally hydrophilic (water-loving), or siloxane (SiOHSi) groups that are typically water-repellant. "What we show," Shrader said, "is that the way that you arrange these two types of chemistries on the surface greatly impacts how water interacts with the surface, which, in turn, impacts physical observable phenomena, like how water spreads on a glass."

In certain processes such as catalysis, for instance, silica (aka silicon dioxide or SiO2) in the form of a whitish powder is used as a support -- the catalyst is attached to the powder grains, which in turn carry it into the process. While silica does not participate directly in the catalysis, the surface molecular composition of the silica grains can influence its effectiveness if the chemical group is predominantly hydrophilic or hydrophobic. The researchers found that if the silica tends to have hydrophilic silanol groups on its surface, it attracts water molecules, in effect forming a "soft barrier" of water molecules that reactants would have to overcome to somehow penetrate to proceed with the desired process or reaction.

"There are always dynamics and the water molecules must exchange their positions, and so that's why it's complicated," said UCSB chemical engineering professor Jacob Israelachvili, whose surface forces apparatus (SFA) measured interaction forces between silica surfaces across water. "You have to break some bond in order for this other bond to form. And that can take time."

It's not just the mere presence of the silanol groups that can affect water adhesion to silica surfaces. The researchers were puzzled by a nonlinear drop in surface water diffusivity -- as measured by the Overhauser dynamic nuclear polarization apparatus in the Han lab -- as the chemical composition of the silica surface moved from hydrophobic to hydrophilic. That mystery was subsequently solved by UCSB chemical engineering professor Scott Shell and his graduate student Jacob Monroe, whose computer simulations revealed the relative arrangement of silanol and siloxane groups on the surface also had an influence on water adhesion.

"If you have the same fraction of water-liking groups and water-disliking groups, by just rearranging them spatially, you can vary water mobility significantly," Han said.

Catalyst-driven processes are not the only thing that can be improved with a molecular understanding of silica-water adhesion. Filtration and chromatography may also be improved.

"It's also important in cleanroom procedures, nanofabrication and microprocessor formation," said Schrader, who pointed out that microprocessors are fabricated on silicon wafer substrates with a thin layer of glass, upon which circuits are laid. "It's important to understand how the actual surface of the silicon wafer looks on a chemical level and how these different metal layers that they deposit on it stick to it and how they appear."

####

For more information, please click here

Contacts:
Sonia Fernandez

805-893-4765

Copyright © University of California, Santa Barbara

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 News Press

News and information

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

Sirrus's Issued Patent Portfolio Continues To Accelerate July 18th, 2018

FEFU scientists reported on toxicity of carbon and silicon nanotubes and carbon nanofibers: Nanoparticles with a wide range of applying, including medicine, damage cells of microalgae Heterosigma akashivo badly. July 18th, 2018

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Chemistry

Sirrus's Issued Patent Portfolio Continues To Accelerate July 18th, 2018

Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides July 13th, 2018

The Institute of Applied Physics at the University of Tsukuba near Tokyo in Japan uses Deben's ARM2 detector to better understand catalytic reaction mechanisms June 27th, 2018

Quantum Interference May Be Key to Smaller Insulators: Breakthrough could jumpstart further miniaturization of transistors June 6th, 2018

Nanofabrication

Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication July 13th, 2018

Possible Futures

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

FEFU scientists reported on toxicity of carbon and silicon nanotubes and carbon nanofibers: Nanoparticles with a wide range of applying, including medicine, damage cells of microalgae Heterosigma akashivo badly. July 18th, 2018

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Tuning into quantum: Scientists unlock signal frequency control of precision atom qubits July 16th, 2018

Chip Technology

Tuning into quantum: Scientists unlock signal frequency control of precision atom qubits July 16th, 2018

Nanometrics to Announce Second Quarter Financial Results on July 31, 2018 July 12th, 2018

Leti and Soitec Launch a New Substrate Innovation Center to Develop Engineered Substrate Solutions: Industry-inclusive hub promotes early collaboration and learning from substrate to system level July 11th, 2018

GLOBALFOUNDRIES Surpasses $2 Billion in Design Win Revenue on 22FDX Technology : With 50 client designs and growing, 22FDX proves its value as a cost-effective solution for power-sensitive applications July 9th, 2018

Discoveries

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

FEFU scientists reported on toxicity of carbon and silicon nanotubes and carbon nanofibers: Nanoparticles with a wide range of applying, including medicine, damage cells of microalgae Heterosigma akashivo badly. July 18th, 2018

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Tuning into quantum: Scientists unlock signal frequency control of precision atom qubits July 16th, 2018

Materials/Metamaterials

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides July 13th, 2018

Carbon is the new black: Researchers use carbon nanotubes to develop clothing that can double as batteries July 10th, 2018

High-power electronics keep their cool with new heat-conducting crystals July 6th, 2018

Announcements

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

Sirrus's Issued Patent Portfolio Continues To Accelerate July 18th, 2018

FEFU scientists reported on toxicity of carbon and silicon nanotubes and carbon nanofibers: Nanoparticles with a wide range of applying, including medicine, damage cells of microalgae Heterosigma akashivo badly. July 18th, 2018

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

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

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

FEFU scientists reported on toxicity of carbon and silicon nanotubes and carbon nanofibers: Nanoparticles with a wide range of applying, including medicine, damage cells of microalgae Heterosigma akashivo badly. July 18th, 2018

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Tuning into quantum: Scientists unlock signal frequency control of precision atom qubits July 16th, 2018

Industrial

Carbon is the new black: Researchers use carbon nanotubes to develop clothing that can double as batteries July 10th, 2018

New sensor technology enables super-sensitive live monitoring of human biomolecules July 3rd, 2018

Researchers present new strategy for extending ductility in a single-phase alloy June 28th, 2018

Cleaning or Etching Items with Unique Geometries Requires Specialized Expertise June 27th, 2018

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