The Photopolymer Science and Technology Award No. 181100, the Outstanding Achievement Award 2018, was presented to Susumu Fujimori (Tokyo University of Science) for his outstanding achievements in photopolymer science and technology, "Pattern Fabrication by Molded Mask Method, A Pioneering Technology of Nanoimprint Lithography".

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The Photopolymer Science and Technology Award No. 182100, the Best Paper Award 2018, was presented to Yusuf Yagci, Gorkem Yilmaz and Mustafa Ciftci (Istanbul Technical University, Republic of Turkey) for their outstanding contribution published in Journal of Photopolymer Science and Technology, 30, (2017) 385-392, entitled "Photoinitiated Metal Free Living Radical and Cationic Polymerizations".

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The Photopolymer Science and Technology Award No. 182200, the Best Paper Award 2018, was presented to Chen-Gang Wang, Feifei Li, and Atsushi Goto (Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University) for their outstanding contribution published in Journal of Photopolymer Science and Technology, 30, (2017) 379-383, entitled "Photo-Controlled Organocatalyzed Living Radical Polymerization and Its Application to Polymer Brush Synthesis on Surface".

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This study aims to investigate fabrication and photolithography of negative-work photosensitive transparent insulation material for one glass solution (OGS) applying in touch panel. In this work, two reactive monomers, namely, dipentaerythritol hexaacrylate (DPHA) and tri (propylene glycol) diacrylate (TPGDA), were respectively blended with the mixture of 50% 1-hydroxy-cyclohexyl-phenyl-ketone and 50% benzophenone, and polyester acrylic oligomer in propylene glycol monomethyl ether acetate (PGMEA); and the photolithography of resulted negative-work photosensitive transparent insulation materials with different solid content was determined by characteristic curve and the optical microscope (OM). As shown in the results, it was found that the photolithographic resolution, which is termed by the ratio of line width to line space, is significantly affected by the solid content of as-prepared negative-work photosensitive polymer. Based on 8 µm line width and space at 1 µm film thickness, the photolithographic resolution of photosensitive polyester acrylate containing 19.7 wt% solid content could reach 1.1 after irradiating by 600 mJ/cm² ultraviolet visible light and developing by 0.01 wt% KOH solution for 60 seconds in this explore.

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The properties of the template material are important for structure replication during nanoimprint lithography. Soft templates used in soft lithography often deform under the pressure applied in the imprint process. This deformation influences the polymer filling effect. A good understanding of the deformation of soft templates and the filling of the polymer is necessary for accurate replication of the micro structure. In this study, the polymer filling, template stress distribution, and template deformation during the nanoimprint lithography process were simulated. The effect of polymer filling is described in terms of the maximum and minimum polymer filling heights. Increasing the template elastic modulus decreases the template deformation. The polymer filling height increases continuously with increasing template elastic modulus. The stress concentration and maximum stress increase with the template elastic modulus. The influence of template deformation on the polymer filling effect is also discussed.

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A semi-alicyclic dianhydride monomer, 4,4'-dihydroxybiphenyldicyclohexanecarboxylate- 3,3',4,4'-tetracarboxylic acid dianhydride (HTA-BP) was prepared according to a modified procedure reported in the literature with trimellitic anhydride as the starting material. A series of semi-alicyclic polyimide (PI) resins were synthesized from HTA-BP and aromatic diamines, including 4,4'-bis[(4-aminophenoxy-2-trifluoromethyl)] biphenyl (6FBAB) for PI-1, 2,2'-bis[(4-aminophenoxy)phenyl]hexafluoropropane (BDAF) for PI-2, 4,4'-diamino- benzanilide (DABA) for PI-3, and 2-chloro-4,4'-diaminobenzanilide (Cl-DABA) for PI-4 via a two-step chemical imidization procedure. The derived PI resins are easily soluble in polar aprotic solvents, such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), and γ-butyrolactone (GBL). High-whiteness PI ultrafine fabrics with the yellow indices lower than 4.0 were successfully prepared by the electrospinning procedures from the PI solutions in DMAc. The PI fabrics exhibited good thermal stability with the 5% weight loss temperatures over 400 ^oC and glass transition temperatures higher than 190 ^oC.

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High sensitivity of O-acyloxime ester, which is widely used as a photo radical polymerization initiator for color resist, was investigated. Introduction of an ether ring structure to the periphery of oxime was aimed at increasing rigidity of dye scaffold. As a result, the absorption spectrum at i-line (365 nm) became sharp, the absorption efficiency was greatly improved, and the sensitivity was increased by about five times as much as conventional linear type oximes by improving the radical generation quantum yield.

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A new optical lithography method for fabricating humpbacked pattern arrays was developed. The patterns were printed by adopting intentionally defocused projection exposure under the condition of very low numerical aperture of 0.089. As a resist, approximately 100-μm thick SU-8 (MicroChem) was used, and appropriate defocuses were 1400-2000 μm. When the exposure time and the defocus were changed, curvature radii of lens patterns were controllable in a wide range of 70-300 μm. The curvature radius became large when the exposure time was extended, and the defocus was reduced. The patterns will be usable as original molds of lenticular lens arrays. In addition, the patterns will also be usable as temporal lenticular lens arrays as they are, because the SU-8 is almost transparent for visible light.

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Numerous micro-slits were opened penetrating through fine stainless steel pipes using laser-scan lithography and electrolytic etching, and meshed pipes were fabricated. Such micro-fabrication technology will be useful for developing bio-medical micro-stents, syringe needles, mesh filters, and others. As original materials, stainless-steel pipes with an outer diameter of 100 μm, a thickness of 20 μm and a length of 40 mm were used. At first, each pipe coated with a positive resist was exposed to a beam spot of violet laser, and multi-slit patterns were delineated by scanning and intermittently moving the pipe in the axial and rotational directions. After the development, each pipe masked by the resist film except the slit pattern parts were etched individually. Electrolytic etching was applied by using an aqueous solution of NaNO₃ and NH₄Cl as an electrolyte. As a result, mesh structures composed of four linearly arrayed 22 slits arranged at every 90^o circumferential angle were fabricated.

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Measurement methods of therapeutic polymer nanoparticles in the blood stream pre-sent issues regarding adequate selectivity and appropriate safety in complex environ-ments with high absorption coefficients, such as proteins and cells in the blood. In light absorption, the energy of photons can be converted into heat by the photothermal effect and re-emitted through luminescence as autofluorescence. In this study, we developed a microfluidic model to investigate the role of the photothermal effect and autofluores-cence in the measurement of fluorescence from polymer nanoparticles in the blood. The increase in blood temperature owing to the photothermal effect was observed using the laser induced fluorescence (LIF) spectroscopy technique. The detection limit of fluo-rescent polylactic acid (PLA) nanoparticles in whole blood was established 21 μg/mL based on the 3σ value. Polymer nanoparticle sensing in the blood is expected to support monitoring of therapeutic drug concentrations inside the body.

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Biosensing devices such as assays require both speed and sensitivity as two integral components for its effectiveness. Within this review, developed three-dimensional (3D) microfiber polystyrene (PS) platforms are leveraged to introduce a means for effectively rapid and sensitive assays. Considered broadly, the 3D structure contributes to an increased surface area for antibody immobilization while the natural hydrophobic nature of PS promotes this immobilization for immunoassay diagnostics. More specifically, rapid antigen capture can be realized by combining this platform with vacuum pressure to mitigate diffusion limitations for antibody-antigen interactions. Alternatively, the increased antibody immobilization density can realize the selective capture and release of circulating tumor cells (CTC). Through both low concentration CTC capture and effective release of said cells, patient-specific cancer care can be achieved.

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There are two major shortcomings when using proteins for biotechnological applications: (1) low protein stability and (2) difficulty in controlling protein function. A possible solution to these problems may be in the use of nanoparticles to encapsulate proteins. Protein encapsulation can increase protein stability by hindering interactions between proteins and the external environment. Moreover, protein function will be suppressed when proteins are encapsulated, and function can be restored when the encapsulated proteins are released by nanoparticle degradation. This attribute of protein-containing nanoparticles allows for the spatiotemporal control of protein function, which is useful in basic research, as well as in various industrial and medical fields. In this review, we will introduce our recent achievements in development of protein-containing nanoparticles that releasing protein by light signal.

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Coordination bonds between catechol-functionalized proteins and metal ions serve as sacrificial bonds that play essential roles in the expression of good mechanical performance and the self-healing properties of mussel byssal threads, which has inspired researchers to develop a range of catechol-based functional polymers. Herein, we investigated the mechanical properties of catechol-functionalized network polymers crosslinked by dual coordination bonds, namely catechol-Ca and catechol-B. As the bonding strengths are different, the viscoelastic properties of these materials can be controlled by changing the relative concentrations of these two bonds. The dual-coordination polymer with a 75:25 ratio of catechol-B:catechol-Ca (PB₇₅Ca₂₅) exhibited a higher Young's modulus and break strength than the corresponding single-coordination polymer (PCa₁₀₀ or PB₁₀₀₀). The chemical structure of the polymer itself remained unchanged; hence this is a facile experimental system for solely investigating the effects of dynamic bonds on the mechanical properties of network polymers.

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Homogeneous hybrid films of azobenzene-based photochromic amorphous molecular materials, 4-[bis(4-methylphenyl)amino]azobenzene (BMAB) and 4-[phenyl(biphenyl-4-yl)amino]azobenzene (PBAB), together with poly(vinyl acetate) (PVAc) were obtained by spin-coating method. Both BMAB-PVAc and PBAB-PVAc films exhibited reversible phase separation-resolution phenomena by thermal treatments. When the resulting phase-separated films were irradiated with 488 nm-laser beam at appropriate temperature, phase transition was found to take place to form homogeneous films.

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α-Allyloxymethyl acrylic (AMA) polymers are radical-curable resins that contain tetrahydrofuran (THF) rings in their main chain and acrylic units in their side chains. AMA polymers are generally cured by ultraviolet light with photopolymerization initiators and are used as adhesive agents, sealants, inks, and resist materials owing to its high adhesiveness, transparency, and thermal tolerance. In this study, the applicability of methyl AMA polymer (PMeAMA) as an electron beam (EB) resist was investigated. PMeAMA performs as a negative-tone resist upon EB irradiation, and the sensitivity of PMeAMA was determined to be 300-400 μC/cm² for a 55 kV EB. This value is comparable to those of poly(methyl methacrylate) (PMMA) and hydrogen silsesquioxane. The radiation-induced early reactions were studied by using pulse radiolysis. The electron scavenging capability of PMeAMA was confirmed, and its electron scavenging rate constant was comparable to that of PMMA. The unique reactivity of PMeAMA with radical cations was observed in dichloromethane solution, and it may be attributed to the presence of THF rings in the main chain of PMeAMA.

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Organic small molecular semiconductors have been promising candidates for the future electronic materials and devices, and their charge transport potentials have been expected to catch-up and surpass the benchmark one in Si - the giant in the semiconductor materials. As represented in the mobility values observed in graphene with μ > 10⁴ cm² V^-1 s^-1, the extended Π-conjugated electron systems provide highly conductive platforms for electrons and holes, however the charge transport in aggregates of conjugated small molecules is disturbed by inter-molecular thermal fluctuations, resulting in the lower mobility of charge carrierreffs in the molecular systems. We have developed a novel assessment technique of charge carrier mobility on the nanoscale molecular aggregates, referred to as time-resolved microwave conductivity (TRMC) measurement, where the non-contact approach minimizes the inter-aggregates issues in the conventional assessment techniques. Particularly, the combination of TRMC with transient absorption spectroscopy (TAS) realizes herein fully experimental non-contact measurement of mobility in supramolecular architectures without structural modulation of the archtectures in the device fabrication protocols. Electron mobility observed in one-dimensional naphthalenediimide (NDI) stacking structures was determined as μ_-,1D = 10^-3-10^-4 cm² V^-1 s^-1 based on the values of photoconductivity Δσ and photo-carrier generation yield φ determined by TRMC and TAS, respectively. The NDI stacked structures with a variety of inter-molecular interactions were systematically examined by the combined spectroscopy systems, revealing the remarkable impact of interactions stabilizing the stacking structures on the mobility values.

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Lignin is one of the natural resources contained in coniferous trees up to 30% in weight, but it has not been utilized as a useful material up to now in contrast to the wide application of celluloses. Recently it was found that modification of the lignin with oligo-ethylene glycol gives "glycol-lignin" which is soluble in various solvent to open the door to practical applications. One of the application is the application to FRP matrix with combination of epoxy resin and DBU as a catalyst. However, a problem is that the polymerization starts before processing to harden the prepolymer because it must be heated about 100 °C for melting and mixing. Therefor those catalysts which are inactive below 100 °C but becomes active above 100 °C is desirable. We have developed thermal base generators, which were prepared by the neutralization of DBU as a strong basic initiator for epoxides with various acids such as a tetraphenylborate, phenolic resin, or phthalate. The DBU salts are inactive below 100 °C, but they generate free base upon heating above 160 °C thermal treatment to initiate hardening of epoxides. The base generating temperature was found to depend on the pK_a of the counter cation of the thermal base generators, and the hardness of the hybrid materials reached as hard as 6H by pencil hardness measurement.

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Photobase generators are key molecules in the development of various photofunctional materials, which induce no degradation or corrosion of substrates in contrast to photoacid generators when they remain in materials. However no photobase generators with strong basicity and good photobase generation efficiency have been developed for practical use up to now. Both 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU) and 1,5-diazabicyclo-[4.3.0]non-5-ene (DBN) are strong organic bases and so photochemical generation of DBN or DBU is an attractive technique for photopolymers. We have investigated the mechanism of photochemistry of DBU and DBN with photo-removable protecting groups by transient absorption measurements. Nitrobenzyl capped DBU (NB-DBU) was converted to a new chemical species without removal of the capped group after photoexcitation, but electron transfer from NB-DBU to thioxanthone (TX) as a sensitizer occurred to accelerate the decomposition of NB-DBU. In contrast to NB-DBN, energy transfer via electron exchange between TX and benzoyl-protected DBN (BZ-DBN) was the key step in the photoinduced decomposition of BZ-DBN upon photoirradiation, as determined by the increase in the photosensitized emission. Thus, elucidation of the photochemical reaction mechanism of the capped bases should contribute to designing novel highperformance photobase generators.

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Morpho butterfly's blue is the structural color given by optical interference, that contradicts its single coloration in too wide angular range. After proven the principle of the coloration by mimicking the specific nanostructures of their scales, we found the reproduced Morpho-color to serve wide applications, because it can produce a brilliant single color in wide angular range with high reflectivity for longtime without chemical pigment. We have then developed various techniques for practical applications of the specific color. One of the remaining issues is to mass-produce the large-area flexible film, which has long been difficult because of the process containing both nano-imprint and multilayer deposition. Thus, we developed a new process using the flexible mold and simple film-detachment system.

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It has long been known that snail shells have an excellent anti-fouling function, as it is said that there are no dirty snails. The snails encountered during the baiu rainy season in Japan always have clean, shining shells. These shells are known to have convex-concave nanoscale structures on their surface (roughness on the order of approximately 200 nm) that promote the formation of a film of water on the shell surface, creating an ultra-hydrophilic nanoscale structure that repels oils and stains. Creating such an ultra-hydrophilic nanoscale structure on a polymer surface should allow us to produce an antifouling polymer sheet. Additionally, producing a tube from a polymer film with this nanoscale structure should make it possible to create a tube with high antifouling properties. The field of technologies based on imitating properties and structures observed in living organisms in nature is called biomimetics. This paper reports on the development of antifouling sheets and tubes with antifouling functions fabricated using the above technologies. The first step was creating a mold with an artificial snail shell structure using ZrO₂ nanoparticles, whose patterns were then transferred to polymer with nanoimprint technology. These antifouling sheets and tubes are expected to see wide use for medical applications.

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The snail shells have 200 nm porous structures, and an oil repellent function in water. Three biomimetic structures were fabricated: a silicon black surface, a silicon substrate having nano pillars, and a soft resin sheet having nano pillars. All these structures have equivalent sizes to the real snail shells, and showed good oil repellent effects. The latter two structures have regularly arranged pillars. The last resin sheet was fabricated by using a silicon mold with nano holes and using nanoimprint technologies. As this sheet is soft metamaterial, it can be processed to other shapes. As an example, a tube with oil repellent inner walls was fabricated and evaluated. Good oil repellent and antifouling effect were experimentally obtained from the water-oil mixture flow test. These results indicate the future advances in medical equipment and infrastructure.

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While sharkskin surface roughness has been hypothesized but remains yet controversial to be capable of achieving turbulent flow control and drag reduction, sharkskin-inspired “riblets” have been reported to be an effective biomimetic design (BMD). Here we address an integrated study of biomimetic riblets inspired by sharkskin denticles by 3D digitizing. Diffuser vanes with BMD sructures were fabricated using the precision cutting and BMD diffusers were assembled. Diffuser’s fluid control was evaluated to confirm the effect of the BMD on fluid control. Our results indicate that the morphological feature in sharkskin denticles likely play a critical role in passively controlling local turbulent flow and points to the potential of denticle-inspired biomimetic riblets for turbulent-flow control in aquatic vehicles as well as other fluid machinery.

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In this paper, we developed a new 3D-printing system for magnetic elastomer, and demonstrated to fabricate artificial cilia. Natural cilia are hair-like organ found in nature. They are effective fluidic system in the natural world that are widely observed on surfaces of microorganisms of creatures, such as Paramecium and throat surface of mammals. Recently, the motion of cilia has been analyzed and mimicked for developing soft actuator, for example, some studies on artificial cilia driven magnetically have been reported. They are small soft actuators, and there are various manufacturing methods for these actuators depending on materials and products. Among them, authors have already developed the concept of a printing system that not only forms a three-dimensional object but also prints out the deformation of the structure. This system can fabricate various shapes of soft actuators without any assembly. In this report, we utilized UV-curable urethane acrylate as a more flexible material than that used in the previous reports, and fabricated artificial cilia by the printer. We set magnetic anisotropy to each cilium and mimicked a metachronal wave, sequential action of plural cilia that causes effective flow.

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