• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1809-1816
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• 2014

This study demonstrates gel-to-fluid transition temperatures of polydiacetylene bilayer vesicles could play important roles in their colorimetric transition temperatures. We prepared five types of polydiaceylene vesicles with 10,12-pentacosadiynoic acid (PCDA) and cholesterol (0-40 mol % of total content). From temperature-dependent observations of the optical signals (colors and UV-vis spectra), the blue-to-red colorimetric transition temperatures of polydiacetylene vesicles were decreased with the cholesterol contents. A further study with microcalorimetry and dynamic light scattering revealed that the polydiacetylene vesicles first underwent gel-to-fluid transitions, which were followed by event(s) responsible for the colorimetric transitions. Energies required for each event were quantified from analysis of the peaks in the microcalorimetry thermograms. The inclusion of cholesterol in the vesicles decreased both the gel-to-fluid and the colorimetric transition temperatures, suggesting that the colorimetric transition of the polydiacetylene vesicles was mediated by the former event although the event was not the direct reason for the color change.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.273-274
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• 2010

• Bulletin of the Korean Chemical Society
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• v.33 no.4
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• pp.1117-1118
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• 2012

• Bulletin of the Korean Chemical Society
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• v.24 no.5
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• pp.667-670
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• 2003

• Applied Chemistry for Engineering
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• v.32 no.2
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• pp.219-223
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• 2021

Considering the current COVID 19 pandemic, herein, we developed a material that can be used to fabricate a device for checking the body temperature of a person who has been exposed to influenza or corona virus. This material was formed by mixing pluronic F127 (F127) with a polydiacetylene (PDA) vesicle, which was formed with 10,12-pentacosadiynoic acid. The color of the system started to change from blue to light purple at 37 ℃, finally turning reddish at 40 ℃. Thus, the developed material can be used to detect changes in body temperature, and thus, detect signs of fever. The mixing ratio of the PDA vesicle and F127 was an important factor for controlling the temperature at which the color change started. The results showed that the color change accompanied by the separation of the PDA vesicle with F127. We believe that this phenomenon plays an important role in reducing the conjugation length in the double and triple bond of PDA.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.282-282
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• 2010

We report a new method of fabrication of polydiacetylene nanowire using liquid bridge-mediated nanotransfer molding (LB-nTM), a direct patterning method for the formation of two- or three-dimensional structures with feature sizes between tens of nanometers and tens of micron over large areas with various materials from a molder to a substrate via a liquid bridge between them. First, we fabricate assembled diacetylene monomer nanowire on the substrate then make it polymerize using 254nm UV-light irradiation. The Polydiacetylene nanowires have been investigated by UV-visible absorption spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM).

• Fibers and Polymers
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• v.7 no.3
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• pp.217-222
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• 2006

Propargyl alcohol was coupled to 2,4-hexadiyne-1,6-diol (HDD) and crystallized in the process of ultraviolet irradiation-induced topochemical polymerization. The HDD polymer crystals were used as one component in the fabrication of organic photovoltaic cells, in combination with fullerene as the electron acceptor. The various structures of the produced photovoltaic cells included bilayer, trilayer, and bulk heterojunction structures. Their photovoltaic properties were analyzed in relation to crystal structure, electrochemical properties, and band structure of the HOD polydiacetylene polymers.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.3083-3087
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• 2013

Diacetylene lipid monomers possess the capability to self-assemble into vesicles via polymerization under ultraviolet irradiation, resulting in the formation of polydiacetylene (PDA) liposomes. Exposure of the polymerized vesicles to external stimuli is known to induce a unique blue-to-red color transition. The cyclic oligosaccharide ${\alpha}$-cyclodextrin known for its use in many applications, such as drug delivery, purification, and stimulus sensing, is able to form an inclusion complex with poly(ethylene glycol) (PEG) in aqueous solution. In this study, we prepared polymeric liposomes with PEG (PEG-PDA) with the aim of improving the stability of the vesicles and colorimetric response toward ${\alpha}$-cyclodextrin. We demonstrated that PEG-PDA liposome displays unique characteristics compared with native PDA liposome and it also shows apparent chromic properties of the inclusion complex formation with ${\alpha}$-cyclodextrin.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2688-2691
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• 2008

This study addresses a microfluidic method to uniformly form diacetylene (DA) liposomes and control their size. DA liposomes are biochemical sensor materials with a unique property such that when they are polymerized to polydiacetylene (PDA) they exhibit non-fluorescent blue to fluorescent red phase transition upon chemical or thermal stress. The liposome size and distribution are important because they significantly affect the phase transition. So far, DA Liposomes, have been prepared by mixing of bulk phases leading to heterogeneous, polydisperse distribution in size. Therefore, additional post-processes are required such as sonication or membrane extrusion to obtain an appropriate size of liposomes. Here, we report a novel strategy using a microfluidic chip and hydrodynamic focusing to form DA liposomes and control their size. Preliminary results obtained by scanning electron microscope (SEM) and dynamic light scattering (DLS) show that the microfluidic strategy generates more monodispersed liposomes than a bulk method.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2696-2699
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• 2008

Microfluidic chips have been frequently utilized to perform biochemical analysis, like cell culture, because they reduce the consumptions of analytes and reagents and automate multi-step analysis processes. It is often critical to monitor temperature in a microchannel for the analyses in order to control a reaction condition of bio or chemical molecules. We propose a novel method to monitor temperature of a microchannel flow by using polydiacetylene (PDA), a conjugated polymer, that has a unique property to transform its color from visible blue to fluorescent red by thermal stress. We inject PDA sensor droplets generated by hydrodynamic instability into a microchannel with a microheater incorporated on the channel bottom. Also, we change the channel temperature by providing the different electric power to the microheater. The results show that the florescence intensity of PDA sensor droplets linearly increases in response to the flow temperature increase within a certain range.