Preserving Lumber With Atomic-Scale Steel Oxide Coating Presents Benefits Over Strain Treating

 Treated and Untreated Lumber in Water

Handled and untreated items of lumber submerged in water. The lumber on the left has been handled utilizing atomic layer deposition. It resists absorbing water even when submerged. On the suitable is untreated lumber proven for comparability. It readily soaks up water, inflicting a colour change inside seconds. Credit score: Allison Carter, Georgia Tech

Strain treating – which includes placing lumber inside a pressurized watertight tank and forcing chemical substances into the boards – has been used for greater than a century to assist stave off the fungus that causes wooden rot in moist environments.

Now researchers on the Georgia Institute of Expertise have developed a brand new technique that would sooner or later substitute typical strain treating as a option to make lumber not solely fungal-resistant but in addition practically impervious to water – and extra thermally insulating.

The brand new technique, which might be reported at this time (February 13, 2020) within the journal Langmuir and collectively sponsored by the Division of Protection, the Gulf Analysis Program, and the Westendorf Undergraduate Analysis Fund, includes making use of a protecting coating of steel oxide that’s just a few atoms thick all through the complete mobile construction of the wooden.

This course of, generally known as atomic layer deposition, is already often utilized in manufacturing microelectronics for computer systems and cell telephones however now could be being explored for brand new functions in commodity merchandise reminiscent of wooden. Like strain therapies, the method is carried out in an hermetic chamber, however on this case, the chamber is at low pressures to assist the gasoline molecules permeate the complete wooden construction.

“It was actually necessary that this coating be utilized all through the inside of the wooden and never simply on the floor, ”mentioned Mark Losego, an assistant professor within the Faculty of Supplies Science and Engineering. “Wooden has pores which might be in regards to the width of a human hair or a bit of smaller, and we used these holes as our pathways for the gases to journey all through the wooden's construction.”

Because the gasoline molecules journey down these pathways, they react with the pore's surfaces to deposit a conformal, atomic-scale coating of steel oxide all through the inside of the wooden. The result’s wooden that sheds water off its floor and resists absorbing water even when submerged.

Of their experiments, the researchers took completed pine 2x4s and minimize them into one-inch items. They then examined infusing the lumber with three completely different sorts of steel oxides: titanium oxide, aluminum oxide, and zinc oxide. With every, they in contrast the water absorption after holding the lumber below water for a time period. Of the three, titanium oxide carried out one of the best by serving to the wooden take up the least quantity of water. By comparability, untreated lumber absorbed 3 times as a lot water.

“Of the three chemistries that we tried, titanium oxide proved the best at creating the hydrophobic barrier,” mentioned Shawn Gregory, a graduate scholar at Georgia Tech and lead writer on the paper. “We hypothesize that that is doubtless due to how the precursor chemical substances for titanium dioxide react much less readily with the pore surfaces and due to this fact have a neater time penetrating deep inside the pores of the wooden.”

Losego mentioned that the identical phenomena exist in atomic layer deposition processes used for microelectronic units.

 Wood Treatment Researchers

From left to proper, Shannon Yee, an affiliate professor within the Woodruff Faculty of Mechanical Engineering, Shawn Gregory, a graduate scholar at Georgia Tech, and Mark Losego , an assistant professor within the Faculty of Supplies Science and Engineering, show the water repellent qualities of a brand new lumber remedy course of based mostly upon atomic layer deposition. Credit score: Allison Carter, Georgia Tech

“These similar titanium oxide precursor chemistries are recognized to higher penetrate and conformally coat complicated nanostructures in microelectronics similar to we see within the wooden,” Losego mentioned. “These commonalities in understanding elementary bodily phenomena – even in what look like very completely different techniques – is what makes science so elegant and highly effective.”

Along with being hydrophobic, lumber handled with the brand new vapor course of additionally resists the mould that ultimately results in rot.

“Apparently, once we left these blocks sit in a damp setting for a number of months, we observed that the titanium oxide handled blocks have been way more proof against mould development than the untreated lumber , ”Gregory added. “We suspect that this has one thing to do with its hydrophobic nature, though there might be different chemical results related to the brand new remedy course of that may be accountable. That's one thing we might need to examine in future analysis. ”

Yet one more good thing about the brand new course of: vapor-treated wooden was far much less thermally conductive in comparison with untreated wooden.

“ Loads of consideration is paid in residence constructing to insulating the cavities between the structural elements of a house, however a large quantity of the thermal losses are attributable to the wooden studs themselves, ”mentioned Shannon Yee, an affiliate professor within the George W. Woodruff Faculty of Mechanical Engineering and a co- writer on the paper with experience in thermal techniques. “Lumber handled with this new course of could be as much as 30 % much less conductive, which may translate to a financial savings of as a lot as 2 million BTUs of vitality per dwelling per 12 months.”

Reference: “Single-Cycle Atomic Layer Deposition ( 1cy-ALD) on Bulk Wooden Lumber for Managing Moisture Content material, Mildew Progress, and Thermal Conductivity ”by Shawn A. Gregory, Connor P. McGettigan, Emily Ok. McGuinness, David Misha Rodin, Shannon Ok. Yee, and Mark D. Losego , 13 February 2020, Langmuir .
DOI: 10. 1021 / acs. langmuir. 9b03273 langmuir. ]

This materials relies upon work supported by the Workplace of Naval Analysis via grant No. N00014-19-1-2162, the Division of Protection via the Nationwide Protection Science & Engineering Graduate Fellowship Program, the Gulf Analysis Program managed by the Nationwide Academies, and a donation from Roxanne Westendorf. Any opinions, findings, and conclusions or suggestions expressed on this materials are these of the authors and don’t essentially replicate the views of the sponsoring companies.

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