자극 감응 색변환 시스템 연구

Abstract

This dissertation describes two types of colorimetric systems that can respond to external stimuli. Firstly, “Turn-On” type solvatochromic sensor systems were designed based on protective layer approach that enables facile identification of a specific solvent. The majority of conventional solvatochromic molecule based sensor systems inevitably display broad overlaps in their absorption and emission bands because they have been designed to undergo colorimetric changes depending on polarity of solvents. As a result, colorimetric differentiation of solvents of similar polarity has been extremely difficult. Herein, we present a tailor made colorimetric and fluorescence “Turn-On” type solvatochromic sensor that enables facile identification of a specific solvent. The unprecedented sensor system displays a colorimetric transition only when a thin protective layer, which protects the solvatochromic materials, is destroyed/disrupted by a specific solvent. The versatility of this strategy was demonstrated by designing a sensor that differentiates chloroform and dichloromethane colorimetrically and performs sequence selective colorimetric sensing. In addition, the approach was employed to construct a solvatochromic molecular AND logic gate. This new strategy should open new avenues for the development of novel solvatochromic sensors. Secondly, photo-responsible colorimetric polymer fiber mats were designed using photochromic molecules encapsulated electrospun fibers based on precursor approach. Rewritable patterned functional images have great utility for applications including displays, optical memory devices and molecular switches. We developed rewritable films utilizing photochromic compound (spiroyran, diarylethene)-embedded electrospun polymer fibers. Electrospinning of a non-colored viscous solution containing a photochromic molecule (spiropyran, diarylethene) and a matrix polymer, such as polystyrene, polyethylene oxide and poly acrylic acid, affords polymer microfibers that are photoswitchable. Photomasked UV irradiation of the nano/microfibers results in the generation of patterned color images owing to the selective transformation of the phtochromic molecules. The color patterns on photochromic molecule-embedded electrospun microfiber system display an excellent write-erase feature without evident color fading.