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Fundamental resarch

Polymers are spaghetti-like molecules that can take a variety of forms depending on the situation. One example is crystals. A crystal is a folded, ordered arrangement of molecular chains. By heating, cooling, tensile, dissolving in liquid, and various other processes, the exact same polymer can be made into a variety of crystals with different properties. This research field provides an in-depth insight into the physical behavior of polymers through the mechanical analysis of polymer materials.

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Gels

Polymer gel is a strange jelly-like substance that behaves like a solid even though more than 90% of its volume is liquid. Because of their brittleness, most conventional polymer gels are not suitable for practical use. In our laboratory, we have succeeded in producing tough gels with high rubber elasticity by controlling the temperature of gel preparation.

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Nanoparticles

It just looks like water?　But if you shake it, heat it up, or add a special liquid... it turns into a strange, jelly-like liquid! Solutions containing "nanoparticles" exhibit such mysterious properties.

Under certain conditions, the nanoparticles dispersed in the liquid form a network structure that transforms the liquid into a jelly-like state called a "gel”. At Hotta Lab, we are working on analyzing the relationship between the molecular structure and the physical properties of such inorganic nanoparticles, and also polymeric micelles. Through this research, we are challenging to develop materials for medical and industrial applications.

Functional polymers

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Antimicrobial polymers

Antimicrobial materials are materials that prevent the growth of bacteria and support healthy living. Among them, antimicrobial polymers applied to train straps and smartphone LCD screens are especially important in preventing the spread of infection.
The Hotta Laboratory aims to obtain long-term antimicrobial properties by devising new methods to give polymers antimicrobial properties.

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Nanofibers

A technique called electrospinning can be used to fabricate fine polymer fibers (nanofibers) with nano-scale diameters.

In the Hotta Laboratory, we are working on nanofibrillation of super engineering plastics, especially those with very high strength and heat resistance. Compared to films, nanofibers have features such as a larger surface area and increased strength, and are used in filters that adsorb certain substances such as fine particles. They are also expected to be applied as a reinforcing material by compounding with other materials. For such characteristics, nanofibrillation of super engineering plastics can be a research of significant importance in polymer chemistry.

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Self-healing materials

What happens if a crack occurs in a material used on the space station? Of course, now we need to go to space to fix the material. However, going to space is costly and risky. Self-healing materials can reduce these costs and risks.
Self-repairing materials are, as the name implies, magical materials that can repair damaged parts by themselves. However, it is not magic, but a scientific material that utilizes physical interactions. Our laboratory is working on the development of such materials for use in the space environment. Furthermore, self-healing materials can contribute to the construction of a recycling-oriented society because they contribute to the longevity of products.

Eco materials

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Biomass plastics

Naturally derived resources are attracting attention as an alternative to petroleum as a raw material for plastics. Currently, most plastic materials are made from petroleum. By contrast, naturally derived resources are resources originated from carbon dioxide in the atmosphere. Thus, the carbon dioxide produced by their combustion does not contribute to increasing the concentration of carbon dioxide in the atmosphere, making them carbon-neutral resources.
Hotta Laboratory focuses on cellulose and lignin, the two major components of wood. By compounding cellulose fibers into polymers, the polymers can be strengthened many times over. Lignin has also been difficult to apply due to its complex structure, but recently it is being converted into a raw material for elastomers. We are currently working to develop rubber materials using substances that can be synthesized from lignin.

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Biodegradable plastic materials

Unlike ordinary plastics, biodegradable plastics are decomposed by microorganisms and disappear when disposed of in the environment, leaving no waste. For this reason, biodegradable plastics have recently attracted attention as environmentally-friendly materials.

Hotta Laboratory has proposed material recycling with biodegradable plastics. However, the constant degradation rate of biodegradable plastics limits their applications. Our goal is to control the degradation rate of biodegradable plastics to enable a wider range of applications.

Medical devices

Hotta Laboratory is conducting research in collaboration with doctors who are actually active in the field of medicine. Our polymer coating and processing technologies will be used to meet the needs of physicians for medical devices such as those listed below. It is a very challenging research to explore engineering approaches based on the understanding of the characteristics and metabolic system of the human body.

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Stents for vascular stenosis

Lifestyle diseases such as diabetes can cause blood vessels in the limbs to narrow, putting patients at risk for ischemic conditions. This is where vasodilator stents come in. However, stents made of metal are incompatible with blood vessels and blood, and can cause new blood clots.
The Hotta Laboratory is working to improve the biocompatibility of metal stents by applying a polymer coating that maintains the reaction to foreign substances. Moreover, the polymer can be filled with a drug to provide concurrent pharmacological treatment. This allows the stent to be safely implanted in the vessel, which ensures long-term blood flow.

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Polymer beads

Instead of administering drugs directly into blood vessels, more efficient drug administration has been attempted by delivering polymer beads filled with drugs. This concept is called a "drug delivery system”, in short, “DDS”.
Hotta Laboratory aims to create microbeads with uniform particle size by molding and processing polymers, and to improve the dispersion of particles, drug filling performance, and accuracy of drug delivery, such as selectivity to cancer cells. Our research has been conducted daily to ensure that the treatment has minimal side effects when actually administered to the human body.

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Contrast agents

Have you ever heard of contrast agents, which are placed inside the body during a CT or MRI scan to depict certain tissues? Many diseases in the human body can be prevented simply by being able to "see" that tissue. A prime example is the lymphatic system.
The lymphatic system is the second largest circulatory system after the vascular system and is deeply involved in the metabolism of the human body. However, because lymphatic vessels are thin and transparent, unlike blood vessels, it is impossible to inject contrast media directly into them.
In the Hotta Laboratory, we are conducting research on indirect lymphatic contrast by injecting contrast agents beneath the skin and allowing them to be taken up by the lymphatic vessels. We use particle size control and surfactant-based approaches to ensure that the contrast agent is efficiently taken into the lymphatic system.