A method to control the charge of nanoparticles on a two-fluid interface to create a better stable system in which its charge can be switched and managed have been found by researchers at Texas A&M University. The potential to interchange these charges on nano particles leads to a surface which can accommodate itself to various applications similar to a durable firefighting operation and even controlled release in some medications.
Dr. Qingsheng Wang, the associate professor in Artie McFerrin Department of Chemical Engineering and holder of the George Armistead '23 Faculty Fellowship at Texas A&M said that on the basis of this they suggested that it will a responsive material. Also, molecular diffusion can be managed if we change the pH value.
The team's research was published in the American Chemical Society's journal, ACS Applied Materials & Interfaces.
Combination of two or more incompatible and immiscible liquid such as oil and water which can be balanced by interference of solid particles is known as emulsion. Gathering of these particles at fluid-fluid interface as swim lanes in a lap pool to avoid coalescence is called Pickering emulsion.
Graphene quantum dots (GQDs) containing zwitterionic properties have made this successful. They balanced the emulsion and controlled the molecular diffusion on the interface by modifying its pH values like a flipping light switch by using sheets of GQDs packed together which measures less than 5 nanometers in thickness. The average human hair is anywhere from 80,000 to 100,000 nanometers wide, according to this outlook.
Functionalized GQDs are basically nanocarbon materials having zwitterionic structure which has the same amount of both positive and negative charges while still remaining electronically neutral.
The two fluids are divided into hydrophobic and hydrophilic when nanoparticles are added to the interface.
This setup can also lead to managing the overall pH of the interface. GODs can be adjusted to block and unblock an oil-water interface by changing pH values. A stable emulsion system is created when the nanoplates on the interface are changed to the same charge which disassembles them.
Wang said that this will help us to design a system which is more efficient in fire suppression and also we can manage the release which is great for drug delivery and oil recovery. It is not that easy and sometimes if we do manage the release then the system itself is not stable, and before the system collapses only one or two cycle is possible.
The research team consists of chemical engineering doctoral student Rong Ma and former chemical engineering doctoral students Dr. Minxiang Zeng, a research scientist at the University of Notre Dame, and Dr. Dali Huang, a process engineer at Formosa Plastics Corporation.
Reference:
Rong Ma et al, Zwitterionic Graphene Quantum Dots to Stabilize Pickering Emulsions for Controlled-Release Applications, ACS Applied Materials & Interfaces (2022).
DOI: 10.1021/acsami.1c23226
by Tushar Gupta
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