A model is being created by IIT-Kharagpur researchers to explain how liquids spread through paper, a finding that can aid in the design and development of low-cost, paper-based diagnostics.
Some such products could be pregnancy test strips, alkalinity or acidity test strips of beauty and baby soaps, paper-strips for checking water quality and medical diagnosis aided by paper-strip tests of urine, saliva and blood. The model can also improve the functions of writing, drawing and painting using pen and paper.
This technique follows the same physical law of diffusion which explains how we write on paper with an ink pen, said researchers at the institute's Department of Mechanical Engineering.
Despite wide use of liquid-infused paper technologies, there are gaps in the understanding of the basic science behind its behaviour. Chakraborty and his students, Kaustav Chaudhury and Shantimoy Kar, help fill that gap by observing ink spreading on filter paper using an electron microscope scanner.
By understanding liquid spread in the paradigm of diffusion, scientists can control it more precisely to create and refine new products that involve liquid spreading through paper.
The results are published in Applied Physics Letters.