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Zain Ahmad, a KAUST master's degree student supervised by Assistant Professor Himanshu Mishra, recently won a best poster award at the 45th International Conference on Micro & Nano Engineering in Rhodes, Greece. Photo by Khulud Muath.
-By A. Ortega, KAUST News
KAUST M.S. student Zain Ahmad recently won a best poster award in the area of "Nanofabrication for Functionality" at the 45th International Conference on Micro & Nano Engineering (MNE2019). The event took place in Rhodes, Greece, from September 23 to 26.
The conference brought together leaders from academia and industry who work in cutting-edge micro and nanofabrication manufacturing with applications in electronics, photonics, energy, environment, chemistry and the life sciences.
Ahmad's award-winning poster was titled "Hydrophobic Desalination Membranes from Common Hydrophilic Materials," and the work it covered was co-authored by KAUST postdoctoral fellowRatul Das, KAUST researcher Sankara Arunachalam, KAUST laboratory lead Ulrich Buttner and KAUST Assistant Professor Himanshu Mishra. Ahmad's poster was chosen from more than 400 posters presented at the event.
Ahmad is a chemical engineer from the Indian Institute of Technology in Kharagpur. He first joined KAUST as a Visiting Student Research Program intern in Mishra's Interfacial Lab (iLab) during the summer of 2018. He then returned to KAUST as an M.S./Ph.D. student in the University's Environmental Science and Engineering program in the fall of 2018. He is now part of the biomimetics and wetting (BMW) subgroup in iLab.
Researchers in iLab pursue multiscale investigations of interfaces of water with water-repellent media such as air, hydrocarbons or perfluorocarbons over length scales of some 11 orders of magnitude.
Their efforts, for instance, include measuring hydrophobic forces between surfaces at sub-nanometer separations; studying chemical reactions on microdroplets of water; designing insect-inspired perfluorocarbon-free water-repellent membranes at the centimeter scale; and conducting agricultural field trials of their technologies for growing more food with less water in plots of 60 meters on a side.
KAUST M.S. student Zain Ahmad (second from right) stands with his best poster award certificate at the 45th International Conference on Micro & Nano Engineering. Photo courtesy of Zain Ahmad.
Ahmad's work presented at MNE2019 covered the first-ever membranes for water desalination using membrane distillation (MD) processes that are derived from water-loving materials.
"So far, MD processes have exclusively utilized water-repellent materials or coatings such as polytetrafluoroethylene and polyvinylidene difluoride," noted Ahmad. "However, these chemicals are vulnerable to heat, [other] harsh chemicals and abrasion and are expensive and non-biodegradable, [which] limits their applications."
To address these challenges, Mishra's team came up with a bio-inspired approach.
"Inspired by the cuticles of springtails (Collembola), [which are] soil-dwelling hexapods, my colleagues developed Gas Entrapping Microtextured Surfaces (GEMs). GEMs robustly entrap air on submersion in liquids, which could lower frictional drag, for example," Ahmad explained. "The crazy thing is that this nature-inspired approach works, regardless of the chemical makeup of the surface."
"As the next step, Prof. Mishra conceived Gas Entrapping Membranes (GEMs) that would robustly entrap air when submerged in wetting liquids. This meant that we could achieve the functions of water-hating membranes from common water-loving materials," he continued.
KAUST Assistant Professor Himanshu Mishra heads the University's Interfacial Lab and supervises M.S. student Zain Ahmad. Photo by Anastasia Khrenova.
To this end, Ahmad joined forces with iLab BMW subgroup members Dr. Ratul Das, Sankara Arunachalam and Edelberto Manalastas. They collaborated with Ahad Syed from the University's Nanofabrication Core Lab to demonstrate the proof-of-concept for silica-GEMs.
Remarkably, silica-GEMS, consisting of water-loving glass, could separate two reservoirs of water for up to six weeks. In contrast, glass membranes with simple cylindrical/non-cylindrical pores imbibe water in less than a minute.
"Next, we used polymethylmethacrylate (PMMA) sheets—[which are] 10 times cheaper than common perfluorocarbon-sheets—to realize GEMs," Ahmad noted. "We optimized inexpensive, scalable techniques such as CO2 laser manufacturing under the guidance of Ulrich Buttner from the [KAUST] Microfluidics Core Laboratory to realize PMMA-GEMs."
"These efforts could lead to greener, economic and robust solutions for applications that previously required perfluorocarbons," stated Mishra. "iLab's curiosity-driven research in biomimetics and wetting has led to five articles thus far, and a couple more irons are in the fire."
"KAUST has been an amazing journey for me, providing world-class facilities and exposure for research and a good balance [of] rich cultural activities," Ahmad said. "iLab in particular has been spurring [on] motivation [for me] with friendly mentors and valuable guidance. I look to forward to [conducting] breakthrough research that could tackle real-life problems in a simple and effective manner."