For the implementation of SERS in microfluidic devices, we propose a rotor structure using SAW as a simple aggregation mechanism. In this study, 45 nm gold nanoparticles were agglomerated in a rotor and evaluated. It was found that the aggregate size increased with increasing supply energy, indicating that this mechanism contributes to aggregate formation. SERS measurements using this mechanism were also successfully performed.

Currently, high-density semiconductor packages have been required to satisfy the demands of realizing high-performance computing network systems. Hybrid bonding is one of the promising processes for 3D-IC package utilizing WoW (wafer on wafer), CoW (chip on wafer) to realize fine vertical interconnection by die stacking. However, the current fabrication processes and materials for hybrid bonding are based on the front-end based technology such as dry processes and Si-based inorganic materials. In this paper, we demonstrated a novel hybrid bonding system using organic materials especially for Epoxy Molding Compound (EMC) and Photo Imageable Dielectric (PID) which are frequently applied to Fan-Out WLP (Wafer Level Package) and PLP (Panel Level Package) with CMP, UV modification and thermal annealing processes.

We developed photocured films from a blend of TiO₂ nanoparticles and dinaphthylfluorene derivatives having acryl and mercapt groups and a photoinitiator by a photo-thermal dual curing technique. The curing properties of the blends were strongly affected by the photo-thermal dual curing conditions. We successfully fabricated films with high refractive indices (1.693 at 589 nm) and a high thermal stability (5% weight loss temperature: 266 ℃).

The photo-isomerization reaction of 2,4,6-tris(benzylthio)-1,3,5-triazine (TBT) structure was investigated for the first time. Pristine TBT was prepared as the model compound. TBT showed good thermal inertness up to 200 ℃ without any thermal isomerization. The photoreaction of TBT under 254 nm irradiation was investigated with UV/vis and FT-IR spectroscopy using the TBT film in poly(methyl methacrylate) (PMMA) matrix. Detailed analysis of the spectra using density functional theory (DFT) calculation revealed that the single enol-keto isomerization at one benzylthio moiety in TBT dominantly proceeded. The refractive index change along with the photo-isomerization of TBT was evaluated with ellipsometry technique, which showed the refractive index increase of +0.0050 at 633 nm.

Photo-induced depolymerization is a useful technique in designing functional materials and polymer recycling. Polyphthalaldehyde (PPA) has been known to be depolymerizable even in solid state. In this study, networked PPAs linked with oxime ether and urethane units have been prepared, and their photo-induced depolymerization was attempted. The networked structure of PPAs was prepared by anionic polymerization of phthalaldehyde monomer (o-PA) initiated with trifunctional oxime and 1,8-diazabicyclo[5.4.0]undec-7-ene to form truxene core bearing three PPA chains, followed by termination with difunctional isocyanates. We could obtain networked PPAs from 1,5-naphthalene diisocyanate, although could not from hexamethylene diisocyanate. Obtained networked polymers were pressed in neat pellets and UV-irradiated with Hg-Xe lamp (>310 nm). By repeated irradiation in solid state and dispersed state in chloroform, almost of the PPAs became soluble in chloroform. In ¹H NMR spectra of the soluble fractions, peaks due to o-PA and phthalide were observed, suggesting the proceeding of almost complete decrosslinking and depolymerization. Trace amount of insoluble powder finally remained and discussed based on its IR spectrum. We also compared the scanning microscope images of PPAs before and after irradiation.

We report the design of pyrene-substituted azobenzene chromophores and their assembly into flat aggregates capable of repeated switching of their absorption and emission properties in response to light and heat. The introduction of a relatively longer butoxy linker between the pyrene and azobenzene (AzBuPy) resulted in the production of more than 90% of cis-azobenzene at the photostationary state of ultraviolet (UV) light, as determined by UV-visible absorption and ¹H NMR spectral data. Flat petal-shaped micrometer-sized structures formed in highly polar DMF-H₂O mixtures did not experience severe disassembly even after sufficient UV light irradiation, and showed excellent photoswitching performance. In addition, we investigated light and heat responses of DPA@AzBuPy aggregates assembled from hydrophobic fluorophore (9,10-diphenylanthracene: DPA) and AzBuPy mixtures.

The stability of the surface potential derived from spontaneous orientation polarization (SOP) in 2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) films was significantly improved by inserting an insulating layer at the electrode interface. The time of 20% potential loss from the initial value was extended from 1.3 days to 64 days in the dark at room temperature. Numerical simulations of the electrostatic potential in the films showed that the electrons accumulate at the surface region of the TPBi films in thermodynamic equilibrium, compensating for the internal electric field to decrease the surface potential. It was suggested that the insulating layer prevents electron injection from the electrode and stabilizes the surface potential.

In this study, we developed a new actuator that can be driven by both magnetic and pneumatic and conducted driving experiments using the fabricated actuator. Soft actuators are widely used as a means of biomimicry. However, many existing actuators that use a single drive source have limited degrees of freedom and deformation capabilities. Recently, hybrid actuators that can be driven by multiple sources have gained attention due to their ability to produce movements that are not achievable by a single drive source. In this study, we fabricated a simple actuator that combines a cylindrical pillar made of silicone material containing magnetic particles with a hollow structure for pneumatic deformation. Three types of actuators with varying diameters and positions of the hollow structure were fabricated, and the drive of each actuator was measured. The pneumatic extensible actuator allows the actuator tip to be manipulated on a fan-shaped two-dimensional plane. The pneumatic bending actuator could manipulate the actuator tip in three dimensions. The actuator with a larger diameter hollow structure could be deformed differently in the same magnetic field by changing the stiffness of the actuator depending on the air pressure. Furthermore, by modifying the hollow structure and the external shape of the actuator, more unique movements can be achieved, and it is expected to be applied to bio-mimicry such as tentacle movement and cilia structure.

Laparoscopes are now widely used in clinical settings. Laparoscopes are particularly useful in detecting cancers and excising affected areas. During laparoscopic operations, however, the spatter of blood and bodily fluids resulting from the excision of the affected area can fog the objective lens. Condensation on the lens caused by temperature differences between the instrument interior and exterior can also obscure vision. Any obstruction of the field of view during the surgical procedure must be addressed by cleaning the lens at the tip; however, doing so prolongs the time required for the procedure, makes it more invasive, and increases patient burdens. Drawing on biomimicry principles, we developed a laparoscope lens with super water-repellent and antifouling properties. This paper reports our results.

Biomimetic antibacterial nanostructures with a height of approximately 310 nm and a bottom diameter of approximately 240 nm were fabricated by microinjection molding for practical mass production in the fields of biology, electronic engineering, and life science. The gas-permeable hybrid mold fabricated by nanoimprint lithography was used as the mold for microinjection molding to improve the incomplete filling and molding defects caused by gas entrainment in cavities during microinjection molding. One same mold could be used repeatedly without cleaning for 200 injection molding cycles. Antibacterial activity evaluation showed that that the antibacterial activity of the fabricated biomimetic antibacterial nanostructures was 15% greater than that of a flat surface. This work establishes the advanced processing technology of high-resolution nanostructures by microinjection molding with the gas-permeable hybrid mold.

This study presents the development of a balloon-type dielectric elastomer actuator (DEA) that utilizes the Maxwell stress generated by applying voltage between electrodes. DEAs have been recognized for their superior responsiveness, durability, and energy efficiency, making them a promising candidate for applications such as artificial muscles. We fabricated two types of DEA using a latex balloon as the elastic material and carbon grease as the electrode to generate inflating and squashed deformations. We conducted experiments to measure and analyze the two types of deformation while varying the size or inner pressure of the balloon and the voltage magnitude. We found that the voltage magnitude affected the magnitude of the deformation in the actuator with inflating deformation, but not in the actuator with squashed deformation. Additionally, we estimated the applied Maxwell stress in the actuator. The developed actuators were capable of producing movements that imitate the behavior of organisms, such as the pufferfish.

Photoresist materials are also used in semiconductor manufacturing and have excellent properties for fine processing. In recent years, lithography technology has enabled microscopic processing. Among them, photoresist materials, which are also used in semiconductor manufacturing, are attracting attention for their potential to contribute to the development of biosensors, bioelectronics, and biotechnology in the life science field. However, photoresist materials use organic compounds in the casting solvent and developing solution, which raises concerns about environmental protection and health and safety. Therefore, it has been difficult to apply them to the life science field. In this study, we used amylose and amylopectin sugar chains to create a photoresist material that can be developed in water without using organic compounds. This material is characterized by its ability to be applied and developed with water and processed without the use of organic compounds. The photoresist patterns were fabricated and surface shapes were observed, achieving a fine fabrication of approximately 8 µm.