Student Profile: Sabrina Sultana

Sabrina Sultana
Sabrina Sultana, a Ph.D. student in the Department of Chemistry. (Note: Photo was taken before the COVID-19 pandemic)

Student Profile: Sabrina Sultana

Current Degree Program: Ph.D., Chemistry

Advisor: Dr. Carl Tripp

Past Degrees: M.S., B.S., Applied Chemistry – University of Dhaka



Sabrina Sultana is a Ph.D. of Chemistry student at the University of Maine. She holds B.S. and M.S. degrees from the University of Dhaka in Applied Chemistry and Chemical Engineering. Since traveling from Bangladesh to Maine in 2014, Sabrina has conducted extensive work in material development, specifically inorganic material synthesis and chemical surface treatment.

What is the focus of your research? When I joined Dr. Carl Tripp’s lab we started working with drinking water treatments using inorganic material synthesis. But, when Oak Ridge National Laboratory (ORNL) teamed up with the University of Maine (UMaine) to form a Hub-and-Spoke program, my research direction shifted. We began working on chemical surface treatments for bio-derived materials, in order to improve the dispersion of cellulose nanofibers into plastics. The goal of this research is to reinvigorate Maine’s forest products industry by using wood-based additives to create plastics that are 100% recyclable. 

How did that affect your thesis? I’ve always enjoyed doing new kinds of research, and I’m more interested in bio-related work. Both the water treatment and the biomaterial dispersions require surface modifications. This research shift has allowed me to continue building my knowledge in material development while allowing me to see how these surface reactions can be applied in very different applications. It has really shaped up my thesis.

How did you choose UMaine? When I decided to move forward with my Ph.D., I looked into universities and professors who were very focused on material science. UMaine’s Chemistry Department fit my focus. The other option I had was in Georgia, but I had never seen snow and the climate in Georgia is very similar to Bangladesh. You don’t understand the cold weather until you feel it!

How long does a Ph.D. program take? Generally, people complete their Ph.D. work within 4-7 years. I’m planning to defend in May 2021, so I will finish in 6.

What’s the most exciting thing you have learned? Right now, the project I’m conducting looks at using supercritical CO2 gas as a solvent or reaction media for material surface modification. Standard practice for these modifications today is to use organic solvents, which have negative safety and environmental risks. Now, we are looking to modify reaction parameters like temperature and pressure to see how that affects cellulose nanofibers (CNF). If supercritical CO2 gas proves to be suitable, then we can introduce a green solvent to industry, which can be separated and recycled, unlike organic solvents.

Why is this important for bio-based plastics? CNF is a very hydrophilic material because of the large number of hydroxyl groups on the molecular surface. In order to blend CNF with polymers, otherwise known as plastics, you need to create a chemical reaction to modify the surface chemistry, reducing the tendency for hydrogen bonding and making it hydrophobic. Then you can proceed to bind CNF with polymers like polyethylene (PE) to make bio-based composites. The surface modification reaction requires a solvent to make the hydroxyl groups more accessible, so your reactants can be physically closer to the CNF molecule. We have been using supercritical CO2 gas as that solvent.

What will you do after you receive your Ph.D.? I’m looking forward to either a post-doc or industrial position. I’m very interested in industrial work, but I also think a post-doc will give me the opportunity to increase my capabilities, publish more work, and improve opportunities later in my career. I know I’d like to continue in the field of bio-related work. The pulp and paper industry has proven to have a significant need for surface treatment and colloidal chemistry expertise, which is my focus.

Who has been most influential in your research? I’d like to thank my advisor, Dr. Carl Tripp, for always guiding me through this journey. I have changed a lot since arriving at UMaine, and this was possible because of my advisor. I’d also like to thank Dr. Doug Gardner and Dr. Lu Wang for their support on the ORNL-UMaine project. I’m very new to composites and they are extremely helpful and friendly. Last but not least, I’d like to thank my husband. My husband is a UMaine Alum and also worked with CNF. When I started this project he was very supportive of my understanding of the material. We talk A LOT about our work and it’s great to have someone always there to answer your questions.