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Thomas Kolibaba (’21) was awarded the NIST National Research Council Postdoctoral Fellowship, funding his postdoctoral research at NIST in Boulder, Colorado following graduation.  Natalie Vest (’24) was awarded the Department of Defense (DoD) Science, Mathematics, and Research for Transformation (SMART) Scholarship, an award that offers full research and education funding, as well as internship opportunities and post-graduation employment at sponsored DoD facilities.

Further information regarding these awards are provided in the links below:

NIST National Research Council Postdoctoral Fellowship

Department of Defense SMART Scholarship

Article on gas barrier nanocoatings fabricated using water-based solution featured in Advanced Science News.

A&M researchers explore the electric potential of a temperature difference

Boundaries are being pushed with layer-bylayer (LbL) technology every day, and the present work has demonstrated the first stretchable gas barrier prepared with this technology. The cover image depicts an American football helmet, representing an oxygen molecule, failing to break through a transparent, stretchable film. On a molecular level, this LbL thin film (≈125-nm thick) uses hydrogen bonding between layers to introduce a bond slipping ability that results in macro-scale stretchiness. This stretchable barrier is important for applications requiring pressurized elastomer materials (e.g., bladders and air bags).

Refining, whether oil or natural gases, can be a costly process because of the need to remove impurities found when extracting them from the ground. Currently expensive materials are used to handle this process.

Texas A&M engineering professors Jaime C. Grunlan and Benjamin A. Wilhite have developed a completely new “game-changing” gas separation membrane that will make the process of extracting these impurities easier, and more importantly, less expensive.

Their work was published recently in the journal Advanced Materials with the title “Highly size-selective ionically crosslinked multilayer polymer films for light gas separation.” They have also filed a patent for this technology due to its commercial potential.

“We use a simple polymer-based film to remove the impurities and it has the promise of a less expensive method for producing purer oil,” said Wilhite, associate professor in the Artie McFerrin Department of Chemical Engineering. “It is all polymer and we are able to get performances comparable to really expensive materials such as mixed matrix membranes and zeolites.”

“The technology is separating gases,” added Grunlan, associate professor in the Department of Mechanical Engineering. “Gas where they mine it is impure and contains different poison gases you don’t want. If you run gas through this membrane what comes out is much purer than what went in on the other side.”

The membrane that Grunlan and Wilhite have developed is a layer-by-layer polymer coating that is comprised of alternating individual layers of common, low-cost polyelectrolytes.

The coating can be made by dipping or spraying, making it very easy to apply to existing gas separation systems. These films separate molecules based on size, the smaller ones such as hydrogen pass through, while larger ones such as carbon dioxide and nitrogen are slowed down.

“You can have multiple membranes in a row and it would keep getting purer and purer each time it went through the membranes,” said Grunlan. “Except for a sheet of metal, nothing has higher selectivity than our coating. This cheap easy coating is the best thing after a pure sheet of metal. The processing is easier and the materials are cheaper.”

The oil and gas industry could stand to be one of the main benefactors of the new technology. Both oil and gas contain impurities that have to be filtered.

For example, crude oil comes out of the ground with sulfur. If the amount of sulfur is greater than 0.5 percent the crude is considered “sour.” Crude with less than 0.5 percent sulfur is considered “sweet,” and is commonly used for processing into gasoline, kerosene and high-quality diesel.

Fully organic thin film nanocomposites were investigated for their superior electrical properties and thermoelectric behavior (G. P. Moriarty, K. Briggs, B. Stevens, C. Yu, J. C. Grunlan, Energy Technol. 2013, 1, 265-272. ). Meso-tetra(4-carboxyphenyl) porphine (TCPP) and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) were used as intrinsically and semiconducting stabilizers, respectively. The electrical conductivity (σ) of these dual-stabilizer organic composites increased to approximately 9500 S m⁻¹ as the concentration of both the multiwalled carbon nanotubes (MWNT) and PEDOT:PSS increased. Replacing MWNT with double-walled carbon nanotubes (DWNTs) increased σ and S to approximately 96000 S m⁻¹ and 70 µVK⁻¹, respectively at 40% DWNTs. Combining semiconducting and intrinsically conductive molecules as CNT-stabilizers has led to a power factor that is among the best for a completely organic, free-standing film (≈ 500 µWm⁻¹K⁻²). These flexible, segregated-network nanocomposites now exhibit properties that rival the more conventional inorganic semiconductors, particularly when normalized by the mass.

(a) Schematic of carbon nanotubes decorated by PEDOT:PSS and TCPP molecules and the junction formed between them. (b) Schematic depicting the formation of a segregated network composite during polymer coalescence as it dries. (c) Photo of a fully dried, free-standing, flexible composite.

Super gas barrier thin films, fabricated with layer-by-layer assembly of polyethylenimine and graphene oxide, exhibit significantly reduced oxygen and carbon dioxide transmission rates. This thin film’s nanobrick wall structure also provides high gas selectivity for hydrogen.

Many current flame retardant (FR) strategies for polymers contain environmentally harmful compounds and/or negatively impact processing and mechanical properties. In an effort to overcome these issues, a effective flame retardant nanocoating comprised of positively charged chitosan (CH) and anionic poly(vinyl sulfonic acid sodium salt) (PVS) was deposited onto flexible polyurethane foam using layer-by-layer (LbL) assembly.

This coating system completely stops foam melt dripping upon exposure to the direct flame from a butane torch. Furthermore, 10 CH-PVS bilayers (~30 nm thick) add only 5.5% to the foam’s weight and completely stop flame propagating on the foam due to the fuel dilution effect from non flammable gases (e.g, water, sulfur oxides, and ammonia) released from the coating during degradation. Cone calorimetry reveals that this same coated foam has a 52% reduction in peak heat release rate relative to an uncoated control. This water-based, environmentally benign nanocoating provides an effective postprocess flame retardant treatment for a variety of complex substrates (foam, fabric, etc.).

New coating could protect furniture without causing health concerns

Inside cover of Advanced Materials:

Researchers at TX A&M have discovered a recipe that renders cotton fabric, the most used natural textile, non-flammable.

Traditional intumescent coatings are composed of both carbon and acid donors, a blowing agent and a binder. Upon addition of heat, all of these components work together as an active barrier separating the substrate from the fire by expanding ~100 times its original thickness.

Below, a 3″ x 12″ piece of cotton fabric coated with 20 BLs of poly(allylamine) and poly(sodium phosphate) has withstood direct contact of a flame for 12 seconds (left). The micrographs display conformally coated fibers and are the first to illustrate nanointumescence (right).

The Polymer NanoComposites lab, lead by materials scientist Professor Jaime C. Grunlan, focuses on three main projects:

1. Gas permeability of nanostructured thin films
2. Flame retardant coatings for foam and fabric
3. Thermoelectric polymer nanocomposites

Outside of the PNC lab, Professor Grunlan actively works to keep higher education a priority in the State of Texas, standing firm on his beliefs that “terrific, well-prepared students” are the product of an institution that pairs quality education with cost.

Texas A&M University System had implemented controversial changes proposed by a conservative research group [that] repeatedly insinuated that such changes were necessary because professors at the state’s flagship universities, A&M and University of Texas at Austin, were not productive enough.

At a regents meeting in May, Professor Grunlan told the A&M board what many of his colleagues were saying. “They’re trashing us, and there’s no response from the regents, from the president,” he said. “The lack of anything is deafening and suggests support of the attacks.”

His speech on YouTube has been viewed nearly 11,000 times.

Click here to find out, What is Vision 2020?

The topic of this newly published journal paper, lead author Morgan A. Priolo, discusses the latest progress in gas barrier technology from the PNC Lab. A 51 nm thick, fully transparent film provides super gas barrier properties that are potentially applicable in food, electronic and pharmaceutical packaging.

These transparent, flexible thin films are fabricated with layer-by-layer assembly (LbL), which is a dipping cycle consisting of a substrate being dipped into alternating cationic and anionic deposition solutions, with spray-rinsing and drying between each deposition. This paper highlights a new quadlayer (QL) system composed of three polymers and a capping clay layer – catioinic polyethylenimine (PEI) and anionic montmorillonite clay (MMT) and poly(acrylic acid) (PAA) – in the dipping sequence PEI/PAA/PEI/MMT.

LbL assembly of polymer and clay creates a nano brick wall structure that forms a highly tortuous path, resulting in a transparent, super gas barrier exhibiting an oxygen permeability orders of magnitude lower than EVOH and SiOx.

Lowest oxygen permeability ever reported for any thin film material! (≤ 5 x 10-22 cm3(STP)·cm/cm2·s·Pa).

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