Facile Phase Transition Measurements for Nanogram Level Liquid Samples Using Suspended Microchannel Resonators

We investigated phase transitions of a PEO-PPO-PEO triblock copolymer and n-heptadecane using a suspended microchannel resonator (SMR). After filling the microchannel of the SMR with each sample in liquid state, changes in the resonance frequency of the SMR were measured as a function of temperature...

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Bibliographic Details
Published inIEEE sensors journal Vol. 14; no. 3; pp. 781 - 785
Main Authors Yun, Minhyuk, Lee, Il, Jeon, Sangmin, Lee, Jungchul
Format Journal Article
LanguageEnglish
Published IEEE 01.03.2014
Subjects
Educational institutions
Frequency measurement
Liquid-rotator transition
Liquids
Microchannel
Resonant frequency
suspended microchannel resonator
Temperature
Temperature measurement
unimer-micelle transition
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Summary:We investigated phase transitions of a PEO-PPO-PEO triblock copolymer and n-heptadecane using a suspended microchannel resonator (SMR). After filling the microchannel of the SMR with each sample in liquid state, changes in the resonance frequency of the SMR were measured as a function of temperature, and then converted into changes in the density of each sample. As temperature increases, PEO-PPO-PEO unimers aggregate and form micelles (unimer-micelle transition), so the density of the polymer decreases and the resonance frequency of the SMR increases. As temperature decreases, n-heptadecane undergoes liquid to rotator phase (liquid-rotator transition), which increases the sample density and decreases the resonance frequency of the SMR. In addition, the liquid-rotator transition of n-heptadecane exhibits a sudden change in the quality factor of the SMR.
ISSN:1530-437X
1558-1748
DOI:10.1109/JSEN.2013.2287887