Morpho butterfly scales have a morphological structure with a nanostructure. The morpho structure has a structure in which nanofins are repeated, and when light hits the structure, light in the visible light region is absorbed, and only blue light is reflected out of the system. Therefore, the morpho butterfly shines bright blue. It has been found that this morpho structure is similar in shape to a fine pattern having a standing wave effect in a semiconductor lithography process. We then report an attempt to fabricate morpho structures using lithographic techniques.

Biomimetics is a field of technologies based on imitating the functions and properties found in living organisms. The application of the super-water-repellent fine structure of lotus leaves to create waterproof products is a well-known example of biomimetics. The present study examined the surface structure of snail shells, which exhibit oleophobic properties oil repellency and explored the feasibility of recreating this structure on the inner surfaces of conventional biliary stents. Observations of snail shells under an electron microscope show a covering of extremely fine protrusions of around 200 nm in size. When water enters the pores between these fine protrusions, a film of water exhibiting super-nanohydrophilic structure forms on the shell. Because water and oil are immiscible, this film repels oil. We would expect stent occlusion to be less likely with a biliary stent having this structure on its inner surface. Biliary stricture caused by bile duct cancer or bile duct obstruction can lead to icterus and may, in serious cases, induce fatal hepatic failure. A surgical procedure that places indwelling biliary stents inside the biliary tract is sometimes performed to secure a passage for bile flow. However, conventional stents are prone to occlusion due to the accumulation of biliary sludge, resulting in the need for a second surgery to replace the stent. This problem is attributable to the polyethylene used to make the biliary stents; polyethylene is susceptible to the adhesion of cholesterol and fats found in the bile, eventually leading to stent occlusions. This paper reports our efforts to develop biliary stents that feature antifouling properties inspired by biomimetics to address this problem; specifically, the development of oleophobic inner stent surfaces featuring super-nanohydrophilic structures inspired by snail shell surfaces.

The snail shell has a 200 nm porous structure and oil repellency in water. The nano-porous structure of 200 nm was found to have an oil repellent effect, but the oil repellent behavior on various micro surfaces was not reported, so the oil repellent evaluation of the micro-surface and the nano-surface was performed. The nanosurface showed excellent oil repellency rating, but it was found that the state of oil repellency is different even at the same nanosize. In order to consider the wetting of oil droplets in water, based on surface morphology, the relationship between super water repellency in air and water super water repellency was discussed. These results are useful for designs that add oil repellent technology to the structure. In the near future, oil repelling effect is expected in view of medical use. Therefore, we will promote oil repellent evaluation and production based on the structure.

Rapidly growing demand of shrinking the features of integrated circuits has accentuated the need for the next generation lithography. Among them, directed self-assembly (DSA) of block copolymers (BCPs) has attracted great interest due to their capability to form ordered nanopattern with high resolution and low cost. In this regard, several groups have investigated some high resolution DSA materials. However, all these materials required high annealing temperature or long annealing time. In this work, a series of polyacrylamide-based fluorine-containing BCPs were synthesized via reversible addition-fragmentation chain-transfer polymerization. One of the BCP materials can form sub-10 nm domains within 1 min at 80 ℃. A domain spacing of BCP with hexagonal structure was further confirmed by SEM on a silicon wafer.

A triblock copolymer (triBCP) containing a short glycidyl methacrylate (GMA) middle block was chemically altered using the efficient thiol-epoxy ring-opening reaction. The resultant modified triBCPs showed significantly different self-assembly behavior from that of the parent triBCP. Analysis by SAXS and TEM showed that this technique can be used to modify the effective interaction parameter (χ_eff) and the self-assembled morphology in the bulk. When modified with strongly interacting hydroxyl groups, χ_eff was found to have increased by a factor of 5. By introducing fluorinated liquid-crystalline molecules, the self-assembled morphology changed from purely lamellar to a complex mixture of lamellae and tetragonally packed cylinders with domain spacing of 20.4 nm and 14.6 nm respectively.

Side-chain fluorination effects on morphological behavior of symmetric polystyrene-b-poly(tert-butyl methacrylate) (PS-b-PtBMA) was investigated using small angle X-ray scattering, where the tBMA units were partially modified into 2,2,2-trifluoroethyl methacrylate (TFEMA) and methacrylic anhydride (MAA) units to form PS-b-P(tBMA-r-TFEMA-r-MAA)s. Above 50% fluorination from 7.8 kg/mol PS-b-PtBMA, a lamellar structure was identified over the entire temperature range up to 240 ℃. However, a 36% fluorination product exhibited the morphological transition from cylindrical to gyroid structures further to disordered state with increasing temperature. This abnormal phase stability was attributed presumably to a transient increase in conformational asymmetry that creates spontaneous interfacial curvatures between the two blocks.

Directed self-assembly (DSA) lithography is one of the promising next-generation lithography technologies. However, there are two main limitations to the use of DSA. One is the narrowness of the pattern size window and the other is the fabrication of the underlayer. To address the former limitation, wide-range DSA has been applied to expand the applicable patterning size while the latter has been achieved by utilizing the newly developed reactive hemicellulose hardening (R2H) technique. In R2H, the hemicellulose unit is selectively hardened by a chemical reaction. In this study, hemicellulose block copolymers for wide-range DSA lithography and its fabrication technology were newly developed. A hemicellulose high-chi block copolymer (OPAL-BCP) and its underlayer were fabricated using R2H. After reactive ion etching of the underlayer with R2H, a pattern depth of over 300 nm and etching selectivity of 24 were obtained.

The directed self-assembly (DSA) of block copolymers (BCPs) is a potentially feasible option for next-generation lithography, due to its potential high resolution and low cost. The smallest domain spacing of conventional BCPs such as polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) are larger than 10 nm, which limits their application in sub-10 nm lithography when compared with EUVL technology. BCPs with high χ value could further reduce the domain spacing to achieve higher resolution. In this work, we synthesized a series of BCPs with biphenyl-typed liquid crystalline (LC) block and fluorine-containing block. With strongly segregated repulsion between isotropic coil and anisotropic LC blocks, the new BCPs yielded highly ordered nanostructures with lamellar and hexagonal morphologies. The smallest feature size was 4.8 nm, showing great potential for sub-5 nm patterning technology.

Block polymers for DSA were prepared using anionic polymer coupling technology and microreactor technology. The effect of the molecular weight on the coupling was investigated. High molecular weight (over 50,000) homo polymers with narrow PDI were prepared in the microreactor. High molecular weight block polymer with narrow PDI was successfully prepared. by coupling of the functionalized PMMA with 1,1-diphenylethylene capped PSt (75,900).

Synchrotron radiation offers great opportunities to improve the understanding of block copolymer morphology and self-assembly processes. In particular, GISAXS characterization is an interesting complementary method to analyze with sub-nanometer resolution the patterns that block copolymer thin films form, in addition to chemical composition. Most of the synchrotron radiation techniques are compatible with block copolymer processes, allowing for an in-situ and real time analysis of the self-assembly processes, what is very important for the analysis of process kinetics. In this contribution, we present the analysis of the self-assembly process of lamellar PS-b-PMMA block copolymer submitted to thermal annealing. The analysis of the 2D-GISAXS patterns allows the evaluation of the block copolymer morphology on formed nanopatterns and about the block copolymer kinetics.

The roll-to-roll process is synonymous with newspaper production. If a similar high-throughput process is developed to fabricate electronics over large areas, it would revolutionize the printed electronics manufacturing process. Rapid fabrication of electrode, including patterning and nanoscale welding, is a necessary integration technique to reduce the duration of the process, but faces difficulties in being realized using conventional methods. This paper discusses material factors that affect printability, in the context of developing a promising fabrication technique called laser induced forward transfer (LIFT); LIFT is non-contact printing technique applied previously to realize simultaneous pattern deposition and nanowelding of Ag nanowire (AgNW)-based electrodes. A photodegradable polymer, which is a key component in the printing process to render droplet acceleration, is investigated with regards to its mechanical and optical properties. Furthermore, the printing process of the AgNW-based electrode is visualized, resulting in deeper understanding of LIFT. Knowledge of these factors will contribute to rapid and precise patterning of AgNW-based electrodes with high stretchability and transparency toward flexible optoelectronics devices.

As the pattern size for the implantation process decreases, KrF lithography has reached its limit in the implementation of micropatterns, calling for the switch to ArF lithography. The change in wavelength for better resolution has led to the development of patterning materials. As a result, the development of a new bottom anti-refractive coatings (BARC) for implant layer patterning with ArF lithography became necessary. In addition to required chromophores for controlling optical properties with ArF lithography, the new BARC system requires a fast etch rate to reduce etch bias during BARC-opening process with plasma. Designing of fast-etch material could be accomplished with utilization of the widely-used model of Ohnishi parameters (O.P.), while designed material revealed the trade-off between etch rate and solubility in organic solvents. In this paper, the design of the material as well as the problem-solving process to address and resolve the trade-off between the desired properties as BARC and the accompanying problems.

WCDU (wafer critical dimension uniformity) has become one of the most momentous factors in the resist process for mass production. Non-uniform WCDU, CD value changes from wafer center to edge, can occur in resist process despite tight critical dimension uniformity (CDU). In this paper, the resist components and the resist process conditions that influence on WCDU variation in negative tone development (NTD) process will be discussed. WCDU was measured with various parameters to understand the causes of current performance.

The contentious issue in ArF lithography is to reduce cost with malti-patterning process. To achieve low defectivity is required at high speed scanner for increasing throughput. Especially, demand of applying top-coat (TC) less process is being increasing recent year at using high speed scanner. The target for defect counts is becoming severe regarding especially logic device. For positive-tone development (PTD) by using alkaline developer, the polarity-change property function of film surface from hydrophobic to hydrophilic after alkaline development process is key to reduce defectivity. The copolymer which has high hydrolysis rate for no swelling design shows also good potential to defect reduction. In addition, it is important to control the uniformization of each material distribution in resist matrix. Especially, aggregation of photo acid generator (PAG) is one of reasons why defect is occurred. Suppressing PAG aggregation is very impotent factor to improve defectivity.

Excited state intramolecular proton transfer (ESIPT) is one of the distinctive photophysical processes of fluorescent compounds and polymers, which induces enhanced fluorescence with a very large Stokes shift. In this work, 6FDA/DCHM/3HPA polyimides (PIs) having bulky –CF₃ groups were synthesized, in which 3HPA is an end-group which exhibits ESIPT with enhanced green emission when irradiated by UV light at 365 nm. Introduction of bulky side chains can improve fluorescent properties via suppression of aggregation induced quenching as well as intermolecular interactions. All the 6FDA-based PI films were colorless and transparent in the visible region, and the PIs having 3HPA end-groups exhibited obvious green emission at 530 nm, when excited at 340 nm. Compared with the corresponding ODPA-based PIs which have no bulky side groups, the 6FDA-based PIs demonstrated significantly higher quantum yields in the solid state (Φ = 0.14−0.25), which is attributable to the looser aggregation structures owing to the bulky and less polarizable –CF₃ group and the absence of energy transfer to/from the non-fluorescent main chain units. Accordingly, the experimental results proved that the introduction of bulky –CF₃ groups using 6FDA moiety is a promising way to create highly fluorescent end-capped PIs.

High gas permeable polymer membranes are required to achieve carbon dioxide capture and storage with high efficiency. In this study, novel mixed matrix membranes (MMMs) based on a chemically modified polymer of intrinsic microporosity and silica nanoparticles were fabricated, and their gas permeation properties were evaluated. The methyltetrazole-modified polymer of intrinsic microporosity (MTZ-PIM) showed higher CO₂/N₂ selectivity than the pristine PIM membrane, and their composite membrane with the surface-modified silica nanoparticles achieved improved CO₂ permeability and good selectivity.

A novel epoxy resin (E-NP-BPDA) having the cardo structure derived from the phthalein dye was prepared from 3,4'-biphthalic anhydride (a-BPDA). a-BPDA was reacted with phenol in methanesulfonic acid, affording a cardo structure. Fixation of the cardo structure was achieved by reaction with methylamine in which cyclic ester was converted to cyclic amide. Further reaction with epichlorohydrin gave E-NP-BPDA. Thermal analysis revealed that E-NP-BPDA has both high thermal stability (T_d5 = 301 ℃) and a low softening point (T_sp= 109 ℃) probably due to the low symmetry and the cardo structure. Curing E-NP-BPDA with slightly excess phenol novolac in the presence of tetraphenylphosphonium tetraphenylborate (TPP-MK) by heating up to 200 ℃ afforded a dark brown thermoset with almost no epoxy groups indicated by IR spectra. The glass transition temperature of the thermoset evaluated by DMA reached 192 ℃ and the value was higher than that of the conventional phenol-novolac-cured bisphenol-A-type epoxy resin.

The evolution of the organic insulated power module and technology of high thermal conductivity and high heat resistance of the key material, which is the Thermally Conductive Electrically Insulating Layer (TCIL), have been reported. TCIL is a polymer / ceramic composite material filled with thermally conductive filler of ceramics in thermosetting resin. Due to the evolution of TCIL and utilization of bonding function that is characteristic of thermosetting resin, the heat dissipation performances have been greatly improved and the downsizing and higher power density of organic insulated module were achieved. Innovations on high performance polymer materials are expected to further improve the performance of power modules in the future.

As increasing demand for advanced electronic devices, finer pitch and higher integration of wirings are required. The trend tends to increase the electrical resistance of wirings. In order to suppress the resistance, it is necessary not only to reduce wiring length, but also to increase the aspect ratio of the finer wiring to ensure its cross-sectional area. We investigated embedded Cu wiring formation process, called as “trench process,” and newly developed a photosensitive material and its seeding process. The photosensitive material showed the capability to form resist pattern (line/space=1 μm/1 μm and aspect ratio=5.0) and Cu wiring (line/space=1.2 μm/1.2 μm and aspect ratio≥3.0) with electroless nickel plating, The material is suitable for trench process.

The novel polyimides having trifluoromethyl groups were synthesized and the introduction of spiropyran groups on their side chain by Mitsunobu reaction were succeeded. The films of obtained polyimides on glass substrates were prepared and the surface wettability of these films were measured before and after UV/VIS light irradiation. As a result, the initial contact angles of the novel spiropyran-containing fluorinated polyimides improved by up to 40°. As expected, the contact angle decreased by UV light irradiation and recovered by VIS light irradiation. However, the change in contact angle was about 10°, which was the same values as the result previously reported.

Electronic devices equip several optical devices such as displays, touch sensors, image sensors (cameras), etc. A lot of kinds of clear coatings are used as important components for the devices. We studied to fuse inorganic nano-filler with siloxane, and developed novel clear coating “PF-series” with heat resistance, high refractive index, and positive photo-sensitivity. We succeeded in grafting siloxane to nano-filler with high refractive index, and the film showed excellent heat and optical stability. Also we designed the siloxane coatings to photosensitize, so photo-positive patterning was enable. These features will promise that PF-series are suitable for the optical device application.

A new para-substituted aromatic ether diamine, bis{4-[4-(4-aminophenoxy)phenoxy]phenyl} ether 1, was synthesized in four steps starting from 4,4’-dibromodiphenyl ether. New aromatic polyimides, with 5 ether linkages per monomer unit, were prepared from this diamine and various tetracarboxylic dianhydrides, pyromellitic dianhydride (PMDA), 3,3’,4,4’-biphenyltetracarboxylic dianhydride (DA-0), 3,3’’,4,4’’-p-terphenyltetracarboxylic dianhydride (DA-1), 3,3’’’,4,4’’’-p-quarterphenyltetracarboxylic dianhydride (DA-2), 3,3’’’’,4,4’’’’-p-quinquephenyltetracarboxylic dianhydride (DA-3), and 3,3’’’’’,4,4’’’’’-p-sexiphenyltetracarboxylic dianhydride (DA-4), by a conventional two-step procedure that included ring-opening polymerization in N-methylpyrrolidone (NMP) and subsequent thermal cyclic dehydration. The polyimides were characterized by wide-angle X-ray diffraction, differential scanning calorimetry (DSC), thermogravimetry (TG), and dynamic mechanical analysis (DMA). PI-PMDA from PMDA and PI-m (m = 0-4) from DA (m = 0-4) had glass transition temperatures (T_g) at 290 ℃ and 200-210 ℃, respectively. The thermal properties, adhesion properties heated at 400 ℃, dielectric constants (ε) and water absorption of the polyimides were compared and discussed on the basis of the number (m) of phenylene units in the dianhydrides.

Rigid aromatic polyimides PI-PP-m (m = 0, 1, 2, 3, 4) were synthesized from p-phenylenediamine and dianhydride DA-m having various numbers (m) of phenylene units, 3,3’4,4’-biphenyltetracarboxylic dianhydride (DA-0), 3,3’’4,4’’-p-terphenyltetracarboxylic dianhydride (DA-1), 3,3’’’4,4’’’-p-quarterphenyltetracarboxylic dianhydride (DA-2), 3,3’’’’4,4’’’’-p-quinquephenyltetracarboxylic dianhydride (DA-3), and 3,3’’’’’4,4’’’’’-p-sexiphenyltetracarboxylic dianhydride (DA-4), by a conventional two-step procedure that included ring-opening polymerization and subsequent thermal cyclic dehydration. The PI-PP-m (m = 0, 1, 2, 3) films were characterized by wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), thermogravimetry (TG), dynamic mechanical analysis (DMA), and stress-strain curves. The properties were compared on the basis of the number (m) of phenylene units. The glass transition temperatures (T_g) were observed at 270-280 ℃ as tan δ peak temperatures of DMA, and the values did not depend on m. The decrement of storage modulus at the T_g was smaller with increasing m. The thermal properties of PI-PP-0 were compared with those previously reported for Upilex-S type polyimides prepared from p-phenylenediamine and DA-0.

We report herein semi-aromatic polyketones having a 1,3-adamantanedimethylene moiety, which consists of a hard alicyclic adamantine-1,3-diyl unit and flexible methylene ones, in a main chain. The polymers enable us to obtain thermally stable, transparent, and flexible films. Notably, the resulting films exhibit low birefringence that is hardly achieved by conventional transparent (colorless) polyimides. We believe that these are applicable to a component for curved, bendable, and foldable displays.

A crystalline acrylic-type polymerizable monomer of diclofenac (DF) was synthesized by linking DF molecule to 2-hydroxyethyl acrylate (HEA). Then, the monomer was polymerized in solid state by vibratory milling with plasma-irradiated lactose powders as postprocessing-free initiators. The characterization of the resulting polymeric prodrug powders by ESR and XRPD analysis confirmed their synthesis successfully. Hydrolysis study of the polymeric prodrugs was carried out in three different buffer solutions (pH 1.2, 6.8 and 8.5) at 37℃. The in vitro release profiles indicated that drug release from the polymeric prodrugs was in sustained manner and highly dependent on pH, in which ca. 9%, 25% and 48% of DF was released in 12 h at pH 1.2, pH 6.8 and pH 8.5, respectively. The results suggested that the studied polymeric prodrug systems in the present investigation can be applied to make a formulation for clinical administration of other drugs as carriers in controlled drug release.

The bioabsorbable magnesium alloy stent exhibits a high dissolution rate; therefore, it faces difficulty in achieving long-term vascular support rigidity. Thus, the control of dissolution rate using a diamond-like carbon (DLC) coating exhibiting excellent biocompatibility is studied. A conventional DLC is usually peeled off from the substrate when the stent expands. The Si-doped DLC (Si–DLC) is considered to be an elastic film candidate for solving this problem. However, the effectiveness of dissolution rate control has not yet been clarified. In this research, we intend to verify the corrosion behavior to confirm the possibility of controlling the dissolution rate of a bioabsorbable magnesium alloy coated with a Si–DLC film using a 13.56 MHz radio-frequency (RF) plasma chemical vapor deposition (CVD) apparatus. Further, the corrosion behavior was examined using electrochemical measurement by cyclic voltammetry. It was observed after repeated oxidation–reduction reaction that Si–DLC can not only drastically diminish the corrosion current value and the pH in the physiological saline solution but also suppress the local corrosion unlike the untreated magnesium alloy and DLC. Thus, the possibility of dissolution velocity control was confirmed.

A liquid crystal polymer (LCP) film were adhered by plasma treatment at atmospheric pressure and thermocompression without using an adhesive. The adhesive strength of plasma treated film increased drastically and plasma treated film indicated cohesive failure inside the film. In addition, the treatment time required to cause cohesive failure was shortened by increasing the discharge power and shortening the distance between the plasma outlet and the sample surface. According to the valence band XPS spectra, it is assumed that the melting point of film surface decreased. The adhesive strength of Ar/He plasma treated film increased and the treatment time required to cause cohesive failure was shortened by containing Ar.

Electrodes that suppress protein adsorption are particularly important for the development of electrochemical biosensors and electroanalysis of biological samples. We studied the electrochemical performances of carbon film electrodes before and after water vapor (H₂O) and ammonia gas (NH₃) plasma treatments. The H₂O plasma treatment substantially increased the surface oxygen concentration and decreased the contact angle. The NH₃ plasma treatment increased the surface nitrogen content to about 5 at %, but a similar amount of oxygen remained on the surface. The sp² bond amounts decreased and the sp³ bond amounts increased after the H₂O plasma treatment, whereas both amounts changed little after the NH₃ plasma treatment. Cyclic voltammetry with the plasma-treated electrodes showed an increase in the peak separation (ΔE) of less than 20 mV for 1 mM Fe(CN)₆^3-/4- containing 100 mg/mL bovine serum albumin (BSA), whereas ΔE of the untreated carbon film increased by about 600 mV. Thus, both plasma-treated electrodes strongly suppressed the protein adsorption. The NH₃ plasma-treated film showed the highest electrochemical activity and lowest redox peak separation with and without BSA despite its higher contact angle value than of the H₂O plasma-treated film. For both plasma-treated films, ΔE did not depend on BSA concentration.

Argon plasma-induced reactions on biocompatible methacrylic polymer brushes were investigated to evaluate the influence on the cell adhesion properties. Polymer brushes of poly(sulfobetaine methacrylate) (PSBMA) and poly(phosphobetaine methacrylate) (PPBMA) were prepared on various substrates using surface-initiated atom transfer radical polymerization techniques. The degradation of PSBMA brushes by Ar plasma irradiation was suppressed than that of PPBMA brushes. This might result from interchain and intrachain interactions of sulfobetaine moieties in PSBMA brushes. Moreover, cell adhesion on plasma-irradiated PSBMA brushes were significantly improved as compared with that to a commercial tissue culture polystyrene dish, suggesting that the resultant surfaces can be used as good scaffolds for cell adhesion.

We performed numerical simulations for investigating atmospheric pressure humid air chemistry triggered by metastable argon atoms fed from an atmospheric pressure plasma jet (APPJ) irradiated on a flowing water surface. We discuss the gas-drag effect caused by the flow of water surface. The gas-drag effect may alter spatial profiles of gas-phase species around the APPJ. It may alter also spatial profiles of the flux of active species impinging on the water surface. The numerical simulations have revealed that the flux profile of OH radicals is surely altered by the gas-drag effect and its flux on the surface is reduced to 1/6 of that on the static surface.

We prepared the polymer nano-film containing drug (5-Fluorouracil, 5-FU) in phosphate buffer saline (PBS, pH 7.4). The size of polymer nano-film containing 5-FU was estimated by dynamic light scattering measurement. The particle size of polymer nano-film at pH 5 was bigger than that at pH 7.4. It was considered that this phenomenon might be ascribed to the electric repulsion among Per-6-ABCD moieties in polymer nano-film at pH 5. The drug release from the polymer nano-film containing 5-FU was also studied at pH 5. It was considered that the increase of particle diameter at pH 5 could induce the release of 5-FU from the polymer nano-film.