TY - JOUR
T1 - Investigation of micro-volume viscosity with janus microbeads based on rotational brownian motion
AU - Chen, Chun Jui
AU - Chen, Wei Long
AU - Phong, Pham Hong
AU - Chuang, Han Sheng
N1 - Funding Information:
Funding: This research was supported by the Ministry of Education and the Ministry of Science and Technology under the grant numbers 107-2221-E-006 -054 -MY3. The authors would also like to thank Vu Thi Thu Ha and Nguyen Thi Ngoc at University of Science and Technology of Hanoi for their kind shares of reagents and instruments.
Funding Information:
This research was supported by the Ministry of Education and the Ministry of Science and Technology under the grant numbers 107-2221-E-006-054-MY3. The authors would also like to thank Vu Thi Thu Ha and Nguyen Thi Ngoc at University of Science and Technology of Hanoi for their kind shares of reagents and instruments.
Publisher Copyright:
© 2019 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2019/3/1
Y1 - 2019/3/1
N2 - Viscosity is an important property of liquids. A viscosity change of aqueous substances that deviates from their normal levels usually implies a compromise in quality due to degradation or microorganism proliferation. Monitoring of macro-scale viscosity can be simply realized by various conventional tools, such as rotational viscometers, capillary tubes, falling bodies, and so forth. Nevertheless, today, micro-volume viscosity measurement remains a challenging endeavor, resulting in rare, expensive, or difficult-to-obtain samples not very well studied. For this reason, a novel technique for micro-viscosity based on rotational Brownian motion is presented in this paper. Janus microbeads were made by coating fluorescent polystyrene beads with gold film. Taking advantage of the bead configuration of half gold/half fluorescence, the rotational Brownian signal was expressed in terms of blinking fluorescent intensity. The characteristic correlation time was derived from the blinking intensity of trace amounts of a selected medium over a certain time period, and results were correlated with viscosity. Given a volume of only 2 µL for each measurement, calibration of a series of glycerol–water mixtures (100%–1% (v/v) water content) yielded good agreement with the expected viscosity predictions over the range of 0.8–574.8 cP. Five common oil products, including lubricant oil, baby oil, food oil, olive oil, and motor oil, were further investigated to demonstrate the feasibility and practicability of the proposed technique. Data measured by the rotational Brownian motion-based diffusometer were comparable with those measured by a commercial rotational viscometer. The method also explicitly showed viscosity degradation after the oils were heated at a high temperature of over 100 ◦ C for 10 min. Evaluation proved the proposed Janus microbead-enabled rotational diffusometric technique to be a promising approach for rapid and micro-scale viscosity measurement.
AB - Viscosity is an important property of liquids. A viscosity change of aqueous substances that deviates from their normal levels usually implies a compromise in quality due to degradation or microorganism proliferation. Monitoring of macro-scale viscosity can be simply realized by various conventional tools, such as rotational viscometers, capillary tubes, falling bodies, and so forth. Nevertheless, today, micro-volume viscosity measurement remains a challenging endeavor, resulting in rare, expensive, or difficult-to-obtain samples not very well studied. For this reason, a novel technique for micro-viscosity based on rotational Brownian motion is presented in this paper. Janus microbeads were made by coating fluorescent polystyrene beads with gold film. Taking advantage of the bead configuration of half gold/half fluorescence, the rotational Brownian signal was expressed in terms of blinking fluorescent intensity. The characteristic correlation time was derived from the blinking intensity of trace amounts of a selected medium over a certain time period, and results were correlated with viscosity. Given a volume of only 2 µL for each measurement, calibration of a series of glycerol–water mixtures (100%–1% (v/v) water content) yielded good agreement with the expected viscosity predictions over the range of 0.8–574.8 cP. Five common oil products, including lubricant oil, baby oil, food oil, olive oil, and motor oil, were further investigated to demonstrate the feasibility and practicability of the proposed technique. Data measured by the rotational Brownian motion-based diffusometer were comparable with those measured by a commercial rotational viscometer. The method also explicitly showed viscosity degradation after the oils were heated at a high temperature of over 100 ◦ C for 10 min. Evaluation proved the proposed Janus microbead-enabled rotational diffusometric technique to be a promising approach for rapid and micro-scale viscosity measurement.
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U2 - 10.3390/s19051217
DO - 10.3390/s19051217
M3 - Article
C2 - 30857368
AN - SCOPUS:85062892733
VL - 19
JO - Sensors
JF - Sensors
SN - 1424-3210
IS - 5
M1 - 1217
ER -