title: Galvanic Cell Type Sensor for Soil Moisture Analysis.
abstract: Here we report the first potentiometric sensor for soil moisture analysis by bringing in the concept of Galvanic cells wherein the redox energies of Al and conducting polyaniline are exploited to design a battery type sensor. The sensor consists of only simple architectural components, and as such they are inexpensive and lightweight, making it suitable for on-site analysis. The sensing mechanism is proved to be identical to a battery type discharge reaction wherein polyaniline redox energy changes from the conducting to the nonconducting state with a resulting voltage shift in the presence of soil moisture. Unlike the state of the art soil moisture sensors, a signal derived from the proposed moisture sensor is probe size independent, as it is potentiometric in nature and, hence, can be fabricated in any shape or size and can provide a consistent output signal under the strong aberration conditions often encountered in soil moisture analysis. The sensor is regenerable by treating with 1 M HCl and can be used for multiple analysis with little read out hysteresis. Further, a portable sensor is fabricated which can provide warning signals to the end user when the moisture levels in the soil go below critically low levels, thereby functioning as a smart device. As the sensor is inexpensive, portable, and potentiometric, it opens up avenues for developing effective and energy efficient irrigation strategies, understanding the heat and water transfer at the atmosphere-land interface, understanding soil mechanics, forecasting the risk of natural calamities, and so on.
authors.affiliation: †Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
authors.forename: Pramod
authors.initials: P
authors.lastname: Gaikwad
authors.affiliation: †Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
authors.forename: Mruthyunjayachari Chattanahalli
authors.initials: MC
authors.lastname: Devendrachari
authors.affiliation: †Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
authors.forename: Ravikumar
authors.initials: R
authors.lastname: Thimmappa
authors.affiliation: †Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
authors.forename: Bhuneshwar
authors.initials: B
authors.lastname: Paswan
authors.affiliation: †Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
authors.forename: Alagar
authors.initials: A
authors.lastname: Raja Kottaichamy
authors.affiliation: ‡Department of Chemistry, Acharya Institute of Technology, Soldevanahalli, Bangalore 560107, India.
authors.forename: Harish
authors.initials: H
authors.lastname: Makri Nimbegondi Kotresh
authors.affiliation: †Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
authors.forename: Musthafa Ottakam
authors.initials: MO
authors.lastname: Thotiyl
mesh_terms: D000535:Aluminum / Q000737:chemistry; D000814:Aniline Compounds / Q000737:chemistry; D011211:Electric Power Supplies; D004566:Electrodes; D004784:Environmental Monitoring; D010084:Oxidation-Reduction; D011199:Potentiometry / Q000295:instrumentation; D012987:Soil / Q000737:chemistry*; D014867:Water / Q000032:analysis*
chemical_list: D000814:Aniline Compounds; D012987:Soil; C416807:polyaniline; D014867:Water; D000535:Aluminum