Citation: Lee, J.; Kim, D.; Kim, T.
Synthesis of Vapochromic Dyes
Having Sensing Properties for Vapor
Phase of Organic Solvents Used in
Semiconductor Manufacturing
Processes and Their Application to
Textile-Based Sensors. Sensors 2022,
22, 4487. https://doi.org/10.3390/
s22124487
Academic Editors: Ki-Hyun Kim
and Deepak Kukkar
Received: 10 May 2022
Accepted: 10 June 2022
Published: 14 June 2022
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Article
Synthesis of Vapochromic Dyes Having Sensing Properties for
Vapor Phase of Organic Solvents Used in Semiconductor
Manufacturing Processes and Their Application to
Textile-Based Sensors
Junheon Lee, Duyoung Kim and Taekyeong Kim *
Department of Textile System Engineering, College of Engineering, Kyungpook National University,
Daegu 41566, Korea; leon1013@hanmail.net (J.L.); endud0609@naver.com (D.K.)
* Correspondence: taekyeong@knu.ac.kr
Abstract:
Two vapochromic dyes (DMx and DM) were synthesized to be used for textile-based
sensors detecting the vapor phase of organic solvents. They were designed to show sensitive color
change properties at a low concentration of vapors at room temperature. They were applied to cotton
fabrics as a substrate of the textile-based sensors to examine their sensing properties for nine or-
ganic solvents frequently used in semiconductor manufacturing processes, such as trichloroethylene,
dimethylacetamide, iso-propanol, methanol, n-hexane, ethylacetate, benzene, acetone, and hexam-
ethyldisilazane. The textile sensor exhibited strong sensing properties of polar solvents rather than
non-polar solvents. In particular, the detection of dimethylacetamide was the best, showing a color
difference of 15.9 for DMx and 26.2 for DM under 300 ppm exposure. Even at the low concentration of
10 ppm of dimethylacetamide, the color change values reached 7.7 and 13.6, respectively, in an hour.
The maximum absorption wavelength of the textile sensor was shifted from 580 nm to 550 nm for
DMx and 550 nm to 540 nm for DM, respectively, due to dimethylacetamide exposure. The sensing
mechanism was considered to depend on solvatochromism, the aggregational properties of the dyes
and the adsorption amounts of the solvent vapors on the textile substrates to which the dyes were
applied. Finally, the reusability of the textile sensor was tested for 10 cycles.
Keywords: semiconductor; textile sensor; solvatochromism; vapochromism; dye
1. Introduction
Huge amounts of organic and inorganic solvents are being used in almost all industries
and research. Most of them are generally recognized as hazardous and toxic to the human
body as well as to the environment. In particular, volatile organic compounds have been
attracting significant attention recently because they are easily vaporized even at room
temperature to a dangerous level of concentration. Therefore, it is necessary to strictly
monitor and reduce the atmospheric concentration, especially indoors. According to recent
reports, organic solvents, which were used for semiconductor manufacturing processes,
caused serious symptoms among workers, such as headaches, dizziness, confusion, nausea,
dyspnea, hepatotoxicity, and central nervous system depression, and this has become a
hotly debated social issue [
1
–
3
]. Various organic solvents are being used in semiconduc-
tor manufacturing processes, mainly washing and cleaning [
4
]. Although they are very
carefully controlled, sometimes the leakage of solvents occurs inadvertently in the liquid
or vapor phase. The leakage of the vapor phase is more serious because it may not be
recognized or noticed easily in advance. Therefore, it is very useful and important for
workers to perceive the leakage of the vapor phase of organic solvents with textile-based
sensors without any electronic devices before the problem becomes serious.
The first role of dyes was the coloration of materials such as fibers, leathers, papers,
plastics, and all kinds of substrates. In addition to this, the application of dyes to organic
Sensors 2022, 22, 4487. https://doi.org/10.3390/s22124487 https://www.mdpi.com/journal/sensors
