The degree of saponification, which is a dissolution characteristic of poly(vinyl alcohol) (PVA), is used to blend PVA to prepare a hydrogel microneedle (MN) patch. The MN patch was manufactured with an adjustable disassembly time using a molding process, and it was confirmed to have morphological stability and excellent needle formation. The permeability of the gelatin sheet, which is analogous to the skin elasticity coefficient of a real human, was confirmed. The penetration ratio had a very high value of 100% and sufficient physical properties to penetrate the skin. In the disassembly experiment, the MN patch was produced with ratios of lower:higher saponification of 6:4 (PVA6), 7:3 (PVA7), 8:2 (PVA8), 9:1 (PVA9), and 10:0 (PVA10). Degradation did not occur for PVA6 and PVA7 but occurred for PVA8, PVA9, and PVA10. A cytotoxicity test to investigate its suitability for use in the human body confirmed the cell viability of 80% or more and nontoxic properties. Therefore, sufficient cell viability was confirmed when compared to the existing products.

Oil spill accidents contaminate the oceanic environment and cause economic distress, and they continue to occur. Many methods have been developed to restore waters contaminated with spilled oil. However, still most commercially available methods are not environmentally or economically sustainable solutions. Therefore, there is a need for the development of sustainable materials with running water treatment capabilities. In recent years, a polyurethane (PU) sponge-based adsorbent has been reported as an oil–water separation and reusable adsorbent. This is because the porous 3D structure of the PU sponge provides a large surface area. However, as the PU sponge has a carboxyl group and an amino group, it exhibits hydrophilicity, so surface modification is essential for oil–water separation. Therefore, to modify the surface of PU to have hydrophobic/oleophilic properties, a hydrophobic/oleophilic adsorbent (HOA) was prepared using graphite and polydimethylsiloxane. On the basis of this, a PU sponge, a porous material, was used to manufacture an adsorbent that can be used in a sustainable and environmentally friendly way. The prepared HOA can selectively adsorb water or oil and can be reused. Furthermore, continuous oil–water separation is possible through a simple flow of fluid. Therefore, it is confirmed that the studied HOA can have great potential for ocean restoration in the future as an adsorbent that mitigates the disadvantages of the currently commercialized method.

We have investigated the structural change of an immiscible blend consisting of two polymers with equal viscosity subjected to a step electric field under shear flow. During the process, three-dimensional images were successfully acquired with a confocal scanning laser microscope, and at the same time, the transient shear stress was also measured. From the images, the interface tensor was calculated. In a blend of polymers with equal viscosity, the total shear stress may consist of the viscous, interfacial, and electric stresses. An experiment was performed to separate these stresses, and the results are discussed in terms of the interface tensor.