Sreenivasan Narayanan, Smart Nonwovens via Wet Film-Assisted Inkjet Printing of  Temperature-Responsive Liquid Crystals

Sreenivasan Narayanan

Degree Type: Ph.D.
Expected Graduation Date: 2025
School/Department: Virginia Commonwealth University
Program/Focus: Mechanical and Nuclear Engineering
Research Project: Smart Nonwovens via Wet Film-Assisted Inkjet Printing of  Temperature Responsive Liquid Crystals
Professor/Faculty Advisor: Christina Tang, Ph.D., VCU; Hong Zhao, Ph.D., VCU

How did you come to have an interest in nonwovens?

I am a doctoral candidate in the department of Mechanical and Nuclear Engineering at Virginia Commonwealth University (VCU), dedicated to conducting research in the Micro/Nano Transport and Printed Devices Laboratory. My research focuses on the drop-on-demand (DOD) printing of thermochromic liquid crystals on nonwoven substrates. Upon graduating as a student, I began my quest for a research project that would be both relevant to the industry and interdisciplinary in nature. It was during this search that I discovered the captivating world of nonwovens and their associated production technologies. The Nonwovens Institute (NWI) emerged as the perfect platform for me, as it provided an opportunity to take on a project that aligns seamlessly with my passions.

Why are your research/findings particularly important/compelling for nonwovens applications?

My research is focused on implementing a drop-on-demand (DOD) printing technique as a rapid, scalable approach to print liquid crystals on a nonwoven substrate to attain patterned, temperature-responsive, “smart” materials. My research also analyzes the interaction between substrate and liquid crystal during the printing process to attain clarity about the change in responsive properties of the liquid crystal. However, directly printing the liquid crystal on the nonwoven fabrics results in faded colors due to the difficulty in controlling the spreading of droplets and the poor alignment of liquid crystal on the substrate. The liquid crystal (LC) alignment has been improved with the assistance of a wet-film coating on the substrate. To gain the maximum advantage of this discovery, I am planning to print cholesteric liquid crystals (CLC) onto a wet film on a nonwoven substrate.

The overall effect of printing parameters will be considered. Also, the effect such conditions as composition, surface treatment, porosity and fiber size on the optical properties of LC, will be studied. Eventually, I am planning to demonstrate the effect in the responsiveness of the resulting smart nonwoven.

Hence the principal goals in this work are to formulate inkjet printable CLC ink and maintain its responsive properties, patterning it on the nonwoven substrate, such as spunbond and meltblown PP for comparison purpose, and to analyze the overall dynamic response.

Potential applications for this research include smart nonwoven materials for respirator facemasks and wound dressings that can communicate information related to respirator facemask fit and wound health, respectively.

Where do you see yourself upon completion of your studies? Where do you see yourself 5-10 years into the future as you progress in your career?

In the immediate future, I am focused on completing my studies and acquiring the necessary skills and knowledge in my field. I am determined to publish my findings in esteemed scientific journals, sharing my research with a broader audience and making significant contributions to my field.

Upon completion of my Ph.D., my objective is to apply my research skills within the industrial sector, specifically in the field of printing. I have a strong desire to work in research and development positions, where I can actively contribute to the creation of innovative materials and tackle intricate engineering problems. I am highly motivated to participate in interdisciplinary research endeavors that have a positive impact on society.

When you are not studying and doing your nonwovens research project, what are your personal interests, hobbies … any activities you would like to highlight?

During my leisure time, I am a nature enthusiast who thrives on the tranquility of hiking trails. Exploring the great outdoors and conquering peaks brings me immense joy. When I’m not immersed in nature, I indulge in captivating movies, exploring various genres, and delving into intriguing plot twists. Additionally, I have a passion for biking, constantly seeking thrill and adventure on two wheels.