Surface engineering of the PLA films for fabricating dexterous humidity sensors (original) (raw)

Abstract

This study presents the surface engineering of the thin films of a biodegradable polymer, poly lactic acid (PLA), for its application in moisture/humidity sensors. The PLA films were deposited on the comb-like pre-patterned indium tin oxide coated glass substrates. The surface morphology of the thin film was modified by using various etchants having different solubilities in PLA. The surface morphology of the thin films was studied by using atomic force microscope and surface profilometer. The modified surfaces feature of the PLA films made them attractive to use as humidity sensors. The humidity sensing characteristics of the surface modified films were investigated by measuring the resistance and capacitance over a wide range of relative humidity levels (20-90% RH). An increase in capacitance and a decrease in resistance was observed by raising the humidity level inside the testing chamber. The proposed PLA based humidity sensor showed small hysteresis, high sensitivity and fast response & recovery time.

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References (21)

  1. H. Farahani, R. Wagiran, M.N. Hamidon, Humidity sensors prin- ciple, mechanism, and fabrication technologies: a comprehensive review. Sensors 14, 7881-7939 (2014)
  2. T. Ahuja, D. Kumar, Recent progress in the development of nano- structured conducting polymers/nanocomposites for sensor appli- cations. Sens. Actuators B 136, 275-286 (2009)
  3. F. ur Rehman, M. Tahir, S. Hameed, F. Wahab, F. Aziz, F. Khalid, M.N. Khalid, W. Ali, Investigating sensing properties of poly- (dioctylfluorene) based planar sensor. Mater. Sci. Semicond. Pro- cess. 39, 355-361 (2015)
  4. H. Lee, S. Lee, S. Jung, J. Lee, Nano-grass polyimide-based humidity sensors. Sens. Actuators B 154, 2-8 (2011)
  5. R. Dabhade, D.S. Bodas, S. Gangal, Plasma-treated polymer as humidity sensing material-a feasibility study. Sens. Actuators B 98, 37-40 (2004)
  6. M. Matsuguchi, S. Umeda, Y. Sadaoka, Y. Sakai, Characterization of polymers for a capacitive-type humidity sensor based on water sorption behavior. Sens. Actuators B 49, 179-185 (1998)
  7. J.-N. Schönberg, V. Kondrashov, A. Prokhorov, J. Rühe, Capaci- tive humidity and dew-point sensing: Influence of wetting of sur- face-attached polymer monolayers on the sensor response. Sens. Actuators B 222, 87-94 (2016)
  8. T. Venugopalan, T. Sun, K. Grattan, Long period grating-based humidity sensor for potential structural health monitoring. Sens. Actuators A 148, 57-62 (2008)
  9. W. Yao, X. Chen, J. Zhang, A capacitive humidity sensor based on gold-PVA core-shell nanocomposites. Sens. Actuators B 145, 327-333 (2010)
  10. X. Chen, L. Liu, Y.Y. Peter, S.S. Mao, Increasing solar absorp- tion for photocatalysis with black hydrogenated titanium dioxide nanocrystals. Science 331, 746-750 (2011)
  11. Z. Chen, C. Lu, Humidity sensors: a review of materials and mechanisms. Sens. Lett. 3, 274-295 (2005)
  12. M. Irimia-Vladu, E.D. Głowacki, G. Voss, S. Bauer, N.S. Saric- iftci, Green and biodegradable electronics. Mater. Today 15, 340-346 (2012)
  13. T. Nakatsuka, Polylactic acid-coated cable. Fujikura Technol. Rev. 40, 39-45 (2011)
  14. K.M. Nampoothiri, N.R. Nair, R.P. John, An overview of the recent developments in polylactide (PLA) research. Bioresour. Technol. 101, 8493-8501 (2010)
  15. S. Sato, D. Gondo, T. Wada, S. Kanehashi, K. Nagai, Effects of various liquid organic solvents on solvent-induced crystallization of amorphous poly (lactic acid) film. J. Appl. Polym. Sci. 129, 1607-1617 (2013)
  16. M. Tahir, M. Hassan Sayyad, F. Wahab, F. Ahmad Khalid, F. Aziz, S. Naeem, M.N. Khalid, Enhancement in the sensing properties of methyl orange thin film by TiO 2 nanoparticles. Int. J. Mod. Phys. B 28, 1450032 (2014)
  17. Z. Ahmad, Q. Zafar, K. Sulaiman, R. Akram, K.S. Karimov, A humidity sensing organic-inorganic composite for environmental monitoring. Sensors 13, 3615-3624 (2013)
  18. M. Björkqvist, J. Salonen, J. Paski, E. Laine, Characterization of thermally carbonized porous silicon humidity sensor. Sens. Actua- tors A 112, 244-247 (2004)
  19. A. Tripathy, S. Pramanik, J. Cho, J. Santhosh, N.A. Abu Osman, Role of morphological structure, doping, and coating of different materials in the sensing characteristics of humidity sensors. Sen- sors 14, 16343-16422 (2014)
  20. Z. Imran, S. Batool, H. Jamil, M. Usman, M. Israr-Qadir, S. Shah, S. Jamil-Rana, M. Rafiq, M. Hasan, M. Willander, Excel- lent humidity sensing properties of cadmium titanate nanofibers. Ceram. Int. 39, 457-462 (2013)
  21. A. Sun, L. Huang, Y. Li, Study on humidity sensing property based on TiO 2 porous film and polystyrene sulfonic sodium. Sens. Actuators B 139, 543-547 (2009)