김종만 교수

Technological advances made in constructing high-resolution instrumentation have enabled fabrication of sophisticated counterfeit products. As a result, the need to develop novel anti-counterfeiting materials and systems is greatly increasing. Accordingly, various functional materials that display distinct chemical, physical as well as optical and electrical properties have been investigated for preventing and detecting counterfeiting. In this feature article, we describe recent strategies that

This Account describes a new strategy for the preparation of label-free sensor systems based on the fluorogenic properties of the conjugated polymer, polydiacetylene (PDA). PDA has been extensively investigated as a sensor matrix, owing to a brilliant blue-to-red color transition that takes place in response to environmental perturbations. It has been known for some time that "blue-phase" PDAs are nonfluorescent while their "red-phase" counterparts fluoresce. For the most part, however, the sign

Owing to the color (blue-to-red) and fluorescence (non-to-fluorescent) changes that take place in response to environmental perturbations, conjugated polydiacetylenes (PDAs) have been actively employed as sensory materials for the detection of biologically-, environmentally- and chemically-important target molecules. Until recently, the majority of PDA sensors have been prepared in the form of aqueous suspensions or Langmuir-type thin films on solid substrates. In order to overcome the limitatio

Hydrochromic materials have been actively investigated in the context of humidity sensing and measuring water contents in organic solvents. Here we report a sensor system that undergoes a brilliant blue-to-red colour transition as well as ‘Turn-On’ fluorescence upon exposure to water. Introduction of a hygroscopic element into a supramolecularly assembled polydiacetylene results in a hydrochromic conjugated polymer that is rapidly responsive (<20 μs), spin-coatable and inkjet-compatible. Importa

Inkjet-printable aqueous suspensions of conjugated polymer precursors are developed for fabrication of patterned color images on paper substrates. Printing of a diacetylene (DA)-surfactant composite ink on unmodified paper and photopaper, as well as on a banknote, enables generation of latent images that are transformed to blue-colored polydiacetylene (PDA) structures by UV irradiation. Both irreversible and reversible thermochromism with the PDA printed images are demonstrated and applied to fl

"Paper" has greatly contributed to the development and spread of civilization. Even in today's "digitalized" world, paper continues to play a key role in socioeconomic growth, as is evidenced by the growth in global paper consumption. Unfortunately, the use of paper has its cost in terms of the exhaustion of world's natural resources. Consequently, new, cost-effective technologies that preserve natural resources are required for this purpose. Functional materials have revolutionized the way peop

While a large variety of conjugated polymers exist, polydiacetylenes (PDAs) remain a major research area among scientists due to their interesting optical, spectral, electronic, and structural properties. Heavily reviewed in regards to their stimuli responsive properties, much is known about the assortment of sensing and detection capabilities of PDAs. In this article, we look more upon the structural diversities of polydiacetylenes that have been achieved in recent years, particularly from a hi

The colorimetric reversibility of polydiacetylene supramolecules, derived from a variety of functionalized diacetylenic lipids, has been subjected to detailed investigation. In an earlier effort, it was shown that polydiacetylene vesicles prepared from PCDA- m BzA 1, bearing terminal m -carboxyphenylamido groups, display complete reversibility upon thermal stimulation [ J. Am. Chem. Soc. 2003, 125, 8976]. The origin and nature of reversible thermochromism in these systems have been elucidated in

High sensitivity and high stretchability are two conflicting characteristics that are difficult to achieve simultaneously in elastic strain sensors. A highly sensitive and stretchable strain sensor comprising a microstructured metal nanowire (mNW)/elastomer composite film is presented. The surface structure is easily prepared by combining an mNW coating and soft-lithographic replication processes in a simple and reproducible manner. The densely packed microprism-array architecture of the composi

A highly elastic skin-like capacitive pressure sensor array ensuring electrical and mechanical robustness based on a thin all-elastomeric platform is presented.

Wearable pressure sensors are crucial building blocks for potential applications in real-time health monitoring, artificial electronic skins, and human-to-machine interfaces. Here we present a highly sensitive, simple-architectured wearable resistive pressure sensor based on highly compliant yet robust carbon composite conductors made of a vertically aligned carbon nanotube (VACNT) forest embedded in a polydimethylsiloxane (PDMS) matrix with irregular surface morphology. A roughened surface of t

Abstract Polydiacetylenes (PDAs), a family of highly π‐conjugated polymers, have unique characteristics associated with their ability to self‐assemble. Disruption of the extensively delocalized enyne backbones of molecularly ordered PDA sidechains induces a blue‐to‐red color change, which has been elegantly applied in the design of chemosensors. Recently, colorimetrically reversible PDAs have received significant attention, not only to gain a better understanding of the fundamentals of PDA chrom

Self-assembled diacetylene vesicles were spotted and immobilized on aldehyde-modified glass substrates using conventional microarray technology. Irradiation of the immobilized diacetylenes allowed generation of nonfluorescent "blue-phase" polydiacetylene (PDA) arrays. Specific interaction of the PDA vesicle arrays with carbohydrates or poly(acrylic acid) solutions afforded fluorescent profiles.