title: Ultrafast response humidity sensor using supramolecular nanofibre and its application in monitoring breath humidity and flow.
abstract: Measuring humidity in dynamic situations calls for highly sensitive fast response sensors. Here we report, a humidity sensor fabricated using solution processed supramolecular nanofibres as active resistive sensing material. The nanofibres are built via self- assembly of donor and acceptor molecules (coronene tetracarboxylate and dodecyl methyl viologen respectively) involved in charge transfer interactions. The conductivity of the nanofibre varied sensitively over a wide range of relative humidity (RH) with unprecedented fast response and recovery times. Based on UV-vis, XRD and AFM measurements, it is found that the stacking distance in the nanofibre decreases slightly while the charge transfer band intensity increases, all observations implying enhanced charge transfer interaction and hence the conductivity. It is demonstrated to be as a novel breath sensor which can monitor the respiration rate. Using two humidity sensors, a breath flow sensor was made which could simultaneously measure RH and flow rate of exhaled nasal breath. The integrated device was used for monitoring RH in the exhaled breath from volunteers undergoing exercise and alcohol induced dehydration.
authors: 1] Chemistry and Physics of Materials Unit and Thematic Unit on Nanochemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064, India [2].
authors: Umesha
authors: U
authors: Mogera
authors: 1] Chemistry and Physics of Materials Unit and Thematic Unit on Nanochemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064, India [2].
authors: Abhay A
authors: AA
authors: Sagade
authors: Supramolecular Chemistry Laboratory, New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064, India.
authors: Subi J
authors: SJ
authors: George
authors: Chemistry and Physics of Materials Unit and Thematic Unit on Nanochemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064, India.
authors: Giridhar U
authors: GU
authors: Kulkarni
mesh_terms: D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D006813:Humidity; D008297:Male; D018625:Microscopy, Atomic Force; D057139:Nanofibers / Q000737:chemistry*; D011083:Polycyclic Compounds / Q000737:chemistry; D012119:Respiration; D014755:Viologens / Q000737:chemistry
chemical_list: D011083:Polycyclic Compounds; D014755:Viologens; C012256:coronene