: pp. 42-48
Lviv Polytechnic National University

Micro-  and nanothermometers with  liquid-phase  sensitive  elements  are made on  the basis of  capillaries  filled with liquid. Important is the kind of liquid (water, alcohol, mercury, etc.), the angle of inclination of the thermometer capillary, and its internal diameter. Currently the need for micro- and nanothermometers with low inertia and accordingly with the small diameter of  the  capillary  is  increasing,  and  information  about  their  inertia,  which  is  necessary,  in  particular,  for  medicine,  becomes insufficient. The time of their thermal inertia is rather small, since the thermal equilibrium of the thermometer and the controlled object is set extremely  fast. However, in reality, the movement of a liquid in a capillary of a thermometer, which determines the readout of the temperature value, due to the change in the thermodynamic conditions during the measurement, is not so rapid to satisfy the metrologists. The experience of studying the spontaneous penetration of liquids in porous micro- and nanochannels of natural structures is limited mainly by works that capture the significance of the influence of initial conditions.

The  features  of  filling  capillaries  of  different  internal  diameters  at  different  angles  of  inclination  are  considered  in  this paper.  It  enables  to work  out  the  technology  of manufacturing  and  application  of  these  thermometers,  and  thus  to  predict  the duration of setting the micro- and nanothermometers’ indications not limiting by thermal inertia.

For this purpose, the Washburn’s and Bosanquet equations are considered. Rate of filling the capillary is affected by fluid viscosity, surface  tension,  length of  the  filled capillary, and its diameter. Since  the viscosity of  the liquid increases slightly with pressure and decreases exponentially with temperature, it is inversely proportional to the rate of liquid penetration or to the rate of moving meniscus.  It was analyzed  the impact of  these  factors on  the micro- and nanothermometers’ performance  that promotes their efficient production and application.

[1]  S.  Yatsyshyn,  B.  Stadnyk,  Ya.  Lutsyk,  “Research  in Nanothermometry. Part 8. Summary”, Sensors & Transducers, vol. 144, iss. 9, p. 1-15, 2012.

[2]  P.  Skoropad,  B.  Stadnyk,  S.  Yatsyshyn,  H.  Pol’ova, “Development  of  Noise  Measurements,  Part  7.  Coriolis  Mass Flowmeter and  its Errors”, Sensors & Transducers, vol. 158,  iss. 11, p. 249-254, 2013.

[3]  B.  Stadnyk,  S.  Yatsyshyn,  O.  Kozak,  “Research  in Nanothermometry. Part  2. Methodical Error Problem  of Contact Thermometry”,  Sensors &  Transducers,  vol.  140,  iss.  5,  p. 8-14, 2012.

[4]  S.  Yatsyshyn,  B.  Stadnyk,  R.  Samchenko,  “CNT nanosensors in the tumors treatment”, Int. J. Biosen. Bioelectron., vol. 2, iss. 6, p. 188-189, 2017.

[5]  X.  Yang,  Z.  Zhou,  F.  Zheng  et  al,  “High  sensitivity temperature  sensor  based  on  a  long,  suspended  single-walled carbon nanotube array”, Micro & Nano letters, IET, vol. 5, iss. 2, p. 157-161, 2010.

[6]  S.Yatsyshyn,  B.  Stadnyk,  Ya.  Lutsyk,  “Research  in Nanothermometry.  Part  3.  Characteristics  of  the  Thermometers with  liquid-  and  solid-phase  sensitive  elements”,  Sensors  & Transducers, vol. 140, iss. 5, p. 15-23, 2012.

[7] G. Khaidarov, A. Khaidarov, A. Mashek, “The physical nature of liquid surface tension”, vestnik St.Petersburg Un., ser.4: Physics and Chemistry, iss. 1, p. 3-8, 2011.

[8] details_en.xsl?node_id=1113

[9]  Powering  nanotechnology  devices  with  novel  surface energy  generators,  Nanowerk  Nanotechn.  Spotlight,  March  5, 2010.

[10] E. Washburn, The Dynamics of Capillary Flow, Phys. Rev., vol. 17 (3), 273, 1921.

[11] H. Akima, "A new method of interpolation and smooth curve fitting based on local procedures", Journ Ass. Comp. Mach., vol. 17, no. 4, p. 589–602, 1970.