- [Show abstract] [Hide abstract] ABSTRACT: We feature the recent developments of patterning of functional polydiacetylene (PDA) on a paper substrate that can be fully integrated with conventional inkjet printing techniques. The use of the paper substrate facilitates the fabrication of flexible, lightweight, and disposable devices. The PDA systems loaded on paper display their uniquely optical properties. In general, diacetylene ink solutions are inkjet-printed on paper and the subsequent UV-irradiation induces photopolymerization of self-assembled DA molecules, leading to the blue phase PDAcoated paper film. The typical blue-to-red transition of the PDA paper film undergoes when it is exposed to a variety of external stimuli. We introduce three types of ink formulation protocols to prepare the PDA precursor solutions that are compatible with inkjet-printing. We also represent the PDA printed paper system and their practical applications, such as counterfeit-proof ink, electrothermochromic paper display, and human sweat pore mapping.
Dataset: Supplementary Information
- [Show abstract] [Hide abstract] ABSTRACT: Much of atmospheric water originates from transpiration, the process by which plants release H2O from pores, known as stomata, that simultaneously intake CO2 for photosynthesis. Controlling stomatal aperture can regulate the extent of water transport in response to dynamic environmental factors including osmotic stress, temperature, light, and wind. While larger leaf regions are often examined, the extent of water vapor release from individual stomata remains unexplored. Using a “brush-on” sensing material, we can now assess transpiration using a water-responsive, polydiacetylene-based coating on the leaves surfaces. By eliciting a fluorometric signal to passing water vapor, we obtained information regarding the activity of individual stomata. In this demonstration, our results prove that this coating can identify the proportion of active stomata and the extent of transpirational diffusion of water in response to different conditions.
- [Show abstract] [Hide abstract] ABSTRACT: Hydrochromic materials, which undergo changes in their light absorption and/or emission properties in response to water, have been extensively investigated as humidity sensors. Recent advances in the design of these materials have led to novel applications, including monitoring the water content of organic solvents, water-jet-based rewritable printing on paper, and hydrochromic mapping of human sweat pores. Our interest in this area has focused on the design of hydrochromic materials for human sweat pore mapping. We recognized that materials appropriate for this purpose must have balanced sensitivities to water. Specifically, while they should not undergo light absorption and/or emission transitions under ambient moisture conditions, the materials must have sufficiently high hydrochromic sensitivities that they display responses to water secreted from human sweat pores. In this Account, we describe investigations that we have carried out to develop hydrochromic substances that are suitable for human sweat pore mapping. Polydiacetylenes (PDAs) have been extensively investigated as sensor matrices because of their stimulus-responsive color change property. We found that incorporation of headgroups composed of hygroscopic ions such as cesium or rubidium and carboxylate counterions enables PDAs to undergo a blue-to-red colorimetric transition as well as a fluorescence turn-on response to water. Very intriguingly, the small quantities of water secreted from human sweat pores were found to be sufficient to trigger fluorescence turn-on responses of the hydrochromic PDAs, allowing precise mapping of human sweat pores. Since the hygroscopic ion-containing PDAs developed in the initial stage display a colorimetric transition under ambient conditions that exist during humid summer periods, a new system was designed. A PDA containing an imidazolium ion was found to be stable under all ambient conditions and showed temperature-dependent hydrochromism corresponding to a colorimetric change near body temperature. This feature enables the use of this technique to generate high-quality images of sweat pores. This Account also focuses on the results of the most recent phase of this investigation, which led to the development of a simple yet efficient and reliable technique for sweat pore mapping. The method utilizes a hydrophilic polymer composite film containing fluorescein, a commercially available dye that undergoes a fluorometric response as a result of water-dependent interconversion between its ring-closed spirolactone (nonfluorescent) and ring-opened fluorone (fluorescent) forms. Surface-modified carbon nanodots (CDs) have also been found to be efficient for hydrochromic mapping of human sweat pores. The results discovered by Lou et al. [ Adv. Mater. 2015 , 27 , 1389 ] are also included in this Account. Sweat pore maps obtained from fingertips using these materials were found to be useful for fingerprint analysis. In addition, this hydrochromism-based approach is sufficiently sensitive to enable differentiation between sweat-secreting active pores and inactive pores. As a result, the techniques can be applied to clinical diagnosis of malfunctioning sweat pores. The directions that future research in this area will follow are also discussed.
- [Show abstract] [Hide abstract] ABSTRACT: "Digitalization" represents one approach to shift society's dependence on paper-based communication. However, thus far, this tactic has not had a significant impact on global paper consumption, which has risen over the past few decades. The escalating demand of paper making and consumption has resulted in an intensified negative effect on the environment. Because of this, the development of rewritable paper or erasable ink appears to be an ideal approach to alleviate the increasing demand for paper. In the investigation described herein, novel light-stimulated (UV-vis), reversible color switching, photochromic diarylethene (DE) derivatives are designed, which serve as cyan, magenta, and yellow colored ink materials for full color ink-jet printing. The structures of the DE derivatives are unique in that they contain hydrophilic ethylene glycol chains that enable them to be compatible with aqueous based, ink-jet printing systems. The results of these studies demonstrate that the new DE derivatives can be used in a printing system based on the "write-erase-write" concept that utilizes the same paper multiple times. The approach appears to be ideal for reducing the negative environmental consequences of paper production and consumption.
- [Show abstract] [Hide abstract] ABSTRACT: A magnetically responsive diacetylene (DA) powder was developed for the visualization of latent fingerprints. A mixture of the DA and magnetite nanoparticles, applied to a surface containing latent fingermarks, becomes immobilized along the ridge patterns of the fingerprints when a magnetic field is applied. Alignment along the ridge structures is a consequence of favorable hydrophobic interactions occurring between the long alkyl chains in the DAs and the lipid-rich, sebaceous latent fingermarks. UV irradiation of the DA-magnetite composite immobilized on the latent fingerprint results in the generation of blue-colored PDAs. Heat treatment of the blue-colored image promotes a blue-to-red transition as well as fluorescence turn-on. A combination of the aligned pale brown colored monomeric state, UV irradiation generated blue-colored PDA state as well as the heat treatment generated red-colored and fluorescent PDA state enables efficient visual imaging of a latent fingerprint, which is deposited on various colored solid surfaces.
- [Show abstract] [Hide abstract] ABSTRACT: Owing to their stimulus responsive color changing properties, polydiacetylenes (PDAs) have been extensively investigated as colorimetric sensors. Thermochromic properties of PDAs have been the central focus of a number of investigations that were aimed not only at gaining a fundamental understanding of the physical basis of the color change but also at developing practical applications as temperature sensors. The thermochromic transition temperature of a PDA polymer is closely related to the melting point of the corresponding diacetylene (DA) monomer. In addition, the majority of PDAs described to date undergo a blue-to-red color change above room temperature because PDAs are generally derived from DA monomers that have melting points above room temperature. In the current study, we developed a series of low temperature colorimetric PDAs that were designed based on the reasoning that removal of the sources for strong headgroup interactions would lower the melting points of the corresponding DA monomers. This strategy was used to design and fabrication of PDA sensors that display color transitions in the range of 5-30°C. Moreover, the thermochromic transition temperatures of the PDAs were found to decrease by ca. 10°C when the alkyl chain length in the DA monomer is truncated by two methylene units. The results of FTIR and Raman spectroscopic analyses suggest that the PDA alkyl chain adopts an all-trans conformation in the blue-phase and some gauche forms exist in the alkyl chain in the red-phase PDA. Finally, the new PDAs are stable up to 300°C, and their processable nature enables them to be fabricated in nanofiber forms by employing an anodized aluminum oxide (AAO) membrane as a template.
- [Show abstract] [Hide abstract] ABSTRACT: Recently, the development of directly writable techniques for depositing functional materials on solid substrates has received great attention. These pen-on-paper approaches enable generation of diverse patterned images on solid substrates in a flexible, easy handling, and inexpensive manner. Herein, the development of a directly writable conjugated polymer is described. Mechanically, drawable colorimetric polydiacetylene (PDA)–wax composites are readily fabricated by using a simple mixing-molding method. Images are mechanically drawn on a paper substrate using the PDA–wax composites, display thermochromism, and mechanothermochromism. The thermochromic transition temperature is dependent on the melting point of the wax and, as a result, can be precisely controlled by the type of wax used. Optical microscopic analysis shows that formation of the DA–wax composite involves movement of wax molecules into a single diacetylene (DA) crystal. This process results in growth of the crystal. Importantly, the PDA crystal, obtained after UV light irradiation, undergoes significant shrinkage upon heating because of the release of monomers and the embedded wax molecules from the crystal. The release of these molecules creates void in the PDA supramolecules, allowing the PDA chains to undergo C–C bond rotation and hence the blue-to-red color transition.
- [Show abstract] [Hide abstract] ABSTRACT: Owing to its stimulus-induced fluorescence ‘turn-on’ feature, polydiacetylene (PDA) has been actively investigated as a label-free sensor matrix. Fabrication of monodisperse PDA particles is important for the efficiency of microarray or microfluidic-based PDA sensor chips. Conventional bulk methods inevitably produce polydisperse mixtures of PDA nanoparticles. Herein we report the synthesis of size-controlled PDA nanoparticles on a microfluidic chip using a staggered herringbone micromixer (SHM), a well-known chaotic mixer. PDA particles of diameters ranging from 36 to 84 nm were readily prepared by adjusting the flow conditions. In addition, use of the SHM method remarkably increased the productivity of the PDA nanoparticles, by about 40 times relative to PDA nanoparticles prepared by means of a hydrodynamic focusing method. The fluorescence intensity of the PDA nanoparticles was found to be dependent upon their size distribution, and a microfluidic channel containing smaller PDA particles was found to emit stronger fluorescence than one containing larger PDA particles.
- [Show abstract] [Hide abstract] ABSTRACT: Fabrication of patterned conjugated polymer images on solid substrate has gained significant attention. Office inkjet printers afford flexible design and fabrication of functional materials on a large-scale and in an inexpensive manner. Although patterning of conjugated polymers on paper using common office inkjet printers have been reported, it has been limited to few examples such as polyaniline (PANI) and poly(3,4-ethylenedioxythiophene) (PEDOT) since only water compatible inks are allowed. Herein, we report fabrication of poly(phenylene vinylene) (PPV) patterns on paper by employing a reactive inkjet printing (RIP) method. Inkjet printing of a hydrophilic terephthaldehyde, bis(triphenyl phosphonium salt) and potassium t-butoxide using a common office inkjet printer allowed efficient fabrication of PPV patterns via in-situ Wittig reaction. In addition, microarrayed PPV patterns were also readily achieved on solid substrates such as glass and PDMS substrates when a piezoelectric dispenser system was employed. The in-situ prepared PPV was found to be insoluble in water and chloroform, thus it allowed efficient removal of unreacted excess reagents and by-products.
- [Show abstract] [Hide abstract] ABSTRACT: Electroactive materials that change shape in response to electrical stimulation can serve as actuators. Electroactive actuators of this type have great utility in a variety of technologies including biomimetic artificial muscles, robotics and sensors. Electroactive actuators developed to date often suffer from problems associated with the need to use electrolytes, slow response times, high driving voltages and short cycle lifetimes. Herein, we report an electrolyte-free, single component, polymer electroactive actuator, which has a fast response time, high durability and requires a low driving voltage (<5 V). The process employed for production of this material involves wet-spinning of a pre-organized camphorsulfonic acid (CSA) doped polyaniline (PANI) gel, which generates long, flexible and conductive (ca. 270 S/cm) microfibers. Reversible bending motions take place upon application of an alternating current (AC) to the PANI polymer. This motion, promoted by a significantly low driving voltage (<0.5 V) in the presence of an external magnetic field, has a very rapid swinging speed (9000 swings/minute) that lies in the range of those of flies and bees (1000-15000 swings/min), and it is fatigue-resistant (> one million cycles).
- [Show abstract] [Hide abstract] ABSTRACT: Hydrochromic materials find great utility in a wide range of applications including humidity sensing and measuring the water contents of organic solvents, as well as substrates for rewritable paper and human sweat pore mapping. Herein, an inkjet printable diacetylene (DA) is described that can be transformed by UV irradiation to a hydrochromic-conjugated polymer on conventional paper. Specifically, an amphiphilic DA that contains an imidazolium ion head-group is found to be compatible with a common office inkjet printer. Various computer-designed images are printed on paper using this substance. UV irradiation of the printed images results in the generation of blue-colored images associated with formation of a polydiacetylene (PDA). The resolutions of the images are almost identical to those generated using a conventional black ink. Importantly, the printed images undergo a blue-to-red color change upon exposure to water and the hydrochromism is found to be temperature dependent. The facile color change that occurs near body temperatures enables use of the hydrochromic PDA-coated paper for rapid and precise mapping of human sweat pores from fingers, palms, and feet. Inkjet printing of an aqueous solution of amphiphilic diacetylene followed by UV-irradiation results in the generation of hydrochromic polydiacetylene on conventional paper. The polydiacetylene-coated paper, which displays temperature-dependent hydrochromism corresponding to a facile color change at near body temperature, enables a rapid and precise mapping of human sweat pores from fingers, palms, and feet.
- [Show abstract] [Hide abstract] ABSTRACT: A three order sensitivity enhancement over a 2D system was achieved with a polydiacetylene-immobilized 3D networked sensor matrix.
- [Show abstract] [Hide abstract] ABSTRACT: Owing to the relative ease of preparation, facile surface modification, and good magnetic property, magnetite-based functional nanoparticles have been extensively investigated in the context of applications to the areas of sensing, imaging, separation and purification. Conventional magnetite pattering methods either require tedious steps and/or suffer from poor resolution. We have developed a very straightforward method for the preparation of patterned magnetite nanoparticles (MNPs). The polymerizable supramolecular approach afforded finely patterned MNPs on a solid substrate after a sequential UV-irradiation-wet etching-calcination process with a MNP-embedded diacetylene film. The patterning process can be readily monitored by the naked eye since each step yields a distinct color corresponding to the polydiacetylene (PDA) (blue and red) and MNP (yellow-brown). The thickness of the MNP film can be also readily manipulated by controlling the amount of NMP employed. The methodology described in the manuscript should be applicable to other metallic nanoparticles.
- [Show abstract] [Hide abstract] ABSTRACT: Owing to the relatively high conductivity and unique redox behavior, polyaniline (PANI) has been one of the most technologically promising conducting polymers. Although various methodologies have been developed, fabrication of PANI microfibers has been a challenging task owing to the poor solubility in most organic solvents. By taking advantage of a microfluidic technology and organic soluble acid labile t-Boc-protected PANI (t-Boc-PANI) as the conducting polymer precursor, fabrication of PANI microfibers in a size-controlled manner is possible. Introduction of a THF solution containing t-Boc-PANI, and dodecylbenzenesulfonic acid (DBSA) as a core flow, and water as a sheath flow into a microfluidic channel with a 3D hydrodynamic focusing effect results in crystallization of the polymer fiber. By changing the flow rate, linear PANI microfibers that range from 16.2 to 39.4 μm in diameter are readily obtained. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
- [Show abstract] [Hide abstract] ABSTRACT: Rational design of a hydrocarbon sensor that enables visual differentiation of saturated aliphatic hydrocarbons (SAHCs) is very difficult owing to the lack of useful functional groups that can interact with the sensor system. Here, we report a microbead embedded with polydiacetylene that undergoes faster swelling and faster blue-to-red color change in response to the hydrocarbons of shorter alkyl chains. Accordingly, visual differentiation among n-pentane, n-heptane, n-nonane and n-undecane was readily achieved. By taking advantage of the collective effect, construction of a sensor system with amplified response was possible. Combination of microfluidic technology (for bead preparation), PDMS (swellable polymeric matrix) and polydiacetylene (colorimetric material) were key to enable this unique hydrocarbon sensor.
- [Show abstract] [Hide abstract] ABSTRACT: A single photomechanical supramolecular nanowire actuator with an azobenzene-containing 1,3,5-tricarboxamide derivative is developed by employing a direct writing method. Single nanowires display photoinduced reversible bending and the bending behavior follows first-order kinetics associated with azobenzene photoisomerization. A wireless photomechanical nanowire tweezers that remotely manipulates a single micro-particle is also demonstrated.
Kyungpook National University
Daikyū, Daegu, South Korea
- School of Computer Science and Engineering
Korea Institute of Science and Technology
Sŏul, Seoul, South Korea
- Center for Biomaterials
Sŏul, Seoul, South Korea
- • Division of Chemical Engineering and Bioengineering
- • College of Engineering
Düsseldorf, North Rhine-Westphalia, Germany
- Institut für Organische Chemie und Makromolekulare Chemie