Electrokinetics Mediated Hydro-Electric Energy Conversion by Professor Suman Chakraborty

Abstract: In the milieu of global warming and energy crisis, frugal yet sustainable and renewable energy resources are critical to the advancement of human civilization. Generating sustainable and stable electricity from mundane and natural sources without necessitating mechanized inputs and sophisticated setups triggers wishful desires and compelling challenges, simultaneously. Miniaturization of various bio-electronics and microfluidic-based lab-on-chip devices has essentially demanded an integrated power source for powering those micro-chips. Towards this end, realizing an alternate source of green energy generation for these microfluidic chips is certainly one of the key concerns. To achieve this feat, many different mechanisms like solar cells, dye sensitized solar cells (DSSCs), bio-mass conversion, microbial energy harvesting etc. have extensively been explored. Despite the inherent advantages of the aforesaid processes, all the underlying principles have certain intrinsic limitations.

Electrokinetic energy conversion mechanisms, mediated by the establishment of a streaming potential (i.e. the potential generated due to the continuous transport of electrolytes), has of late emerged to be as effective alternative. Recent studies have successfully demonstrated the application of this paradigm, albeit in a sophistically controllable laboratory environment that cannot possibly be replicated for catering the functionalities of point of care devices in resource-limited settings. In addition, the reported devices on electrokinetic energy conversion necessitate elaborate device fabrication, expensive consumables and trained personnel. Furthermore, these devices not only demand very intricate operational module, but also do not inherently integrate with low cost analytical platforms; which eventually makes the entire paradigm expensive.

By exploiting a new paradigm of surface charge-salinity-fluidic coupling over interfacial scales, we explore electrokinetics on a simple ‘paper-and-pencil’ based platform as a greener alternative for on-chip energy harvesting. The primary advantages of such a platform are the self-propelling nature of the input flow through an exploitation of intrinsic capillary transport in paper pores (to this end, no syringe pump or equivalent actuation is necessary), and an explicit integrability with paper based diagnostic platforms for point of care applications. These features empower the device with a favorable functionality in extremely challenging and resource limited settings in an ultra-low cost paradigm. As a consequence, the intrinsic porous capillaries in the paper structure drive a surface tension driven flow that induces ionic convection necessary for the establishment of an electrical potential across the device, resulting in a favourable direct exploitation and conversion of surface energy into electrical power.

Natural drying of wet clothes is common in daily lives, which is a ubiquitous process ideally suited for harvesting thermal energy from the incipient ambient. By introducing fabrication of simply-designed channels on textile pieces for achieving guided transportation of saline water and drawing analogies of the later with evaporative transport across the parts of a living plant, here we further demonstrate an extremely frugal, simple and viable approach of harvesting electrical power using cellulose-based fiber cloth. Instead of resorting to the deployment of specially-structured and delicately-fabricated substrates towards achieving this feat, we employ regular cellulose-based wearable textile as a medium for ionic motion though the interlace fibrous nano-scale network by capillary action, inducing an electric potential in the process. The device design inherently exploits a large transpiration surface for achieving a sustainable salt-ion-flux migration, through natural evaporation effect over nanometer scales. We have also conducted a field trial for validating our proposition in a resource-poor village, with a vision of addressing the underprivileged community at large. This may be further up-scaled massively by systematically drying a large set of regular wearable garments under the sun-light. This eventually culminates into a utilitarian paradigm of low-cost power harvesting in extreme rural settings.

Biosketch: Suman Chakraborty is a Professor in the Mechanical Engineering Department as well as an Institute Chair Professor of the Indian Institute of Technology Kharagpur, India, and Sir J. C. Bose National Fellow as bestowed by the Department of Science and Technology, Government of India. He is currently the Dean of Sponsored Research and Industrial Consultancy. Formerly, he was the Head of the School of Medical Science and Technology. His current areas of research include microfluidics, nanofluidics, micro-nano scale transport, with particular focus on biomedical applications. He has been awarded the Santi Swaroop Bhatnagar Prize in the year 2013, which is the highest Scientific Award from the Government of India. He has been elected as a Fellow of the American Physical Society, Fellow of the Royal Society of Chemistry, Fellow of ASME, Fellow of all the Indian National Academies of Science and Engineering, recipient of the Indo-US Research Fellowship, Scopus Young Scientist Award for high citation of his research in scientific/technical Journals, and Young Scientist/ Young Engineer Awards from various National Academies of Science and Engineering. He has also been an Alexander von Humboldt Fellow, and a visiting Professor at various leading Universities abroad. He has 400+ prestigious International Journal publications to his credit.

Date/Time:
Date(s) - Sep 24, 2019
10:00 am - 11:00 am

Location:
47-124 Engineering IV
420 Westwood Plaza Los Angeles CA