MAHE researchers discover technique of making water-repelling surface

Manipal: Researchers at Manipal Academy of Higher Education, Manipal have discovered a new, laser-based technique of fabricating a new class of water-repelling material surfaces. Superhydrophobicity is the term used to describe surface properties that cause water to “repel/bounce” and “roll off”; such properties are widely seen in nature by plants (e.g. lotus leaf)  and aquatic animals, water birds etc.  to repel water, to stay clean and, sometimes, even to permit underwater respiration.

The researchers, Dr. Sajan D. George along with Dr. Jijo Easo George, Dr. Unnikrishnan V. K, Dr. Santhosh Chidangil and Dr. Deepak Mathur at the Department of Atomic and Molecular Physics have succeeded in mimicking such natural phenomena by judicious use of a ultrafast (femtosecond) laser to induce, in controlled manner, roughness on surfaces coated with metal nanoparticles. Their immediate aim was to fabricate flexible surfaces that could be used to detect ultra low concentration of chemicals.

This type of detection capability opens many new avenues in a gamut of applications like detection of minute traces of explosives molecules, drugs, toxins etc. and biomedical applications involving real time  monitoring of extremely low levels of markers in body fluids (e.g. blood serum, saliva, tears, sweat etc.) for the early detection and diagnosis of diseases. 

All such applications are, according to MAHE scientists, non-invasive or minimally invasive.  In experiments that the MAHE scientists have recently reported in a paper published in the prestigious journal, Sensors and Actuators B:Chemical ((https://doi.org/10.1016/j.snb.2018.05.155), the initial work involved the laser-fabrication of a hierarchically micro-nanoscale patterned acrylic material (polymethylmethacrylate, PMMA). This acted as a master structure to create flexible spectroscopy substrates on biocompatible and optically transparent silicone polymer.