Taisuke Banno

Self-propelled oil droplets in a nonequilibrium system have drawn much attention as both a primitive type of inanimate chemical machinery and a dynamic model of the origin of life. Here, to create the pH-sensitive self-propelled motion of oil droplets, we synthesized cationic surfactants containing hydrolyzable ester linkages. We found that n-heptyloxybenzaldehyde oil droplets were self-propelled in the presence of ester-containing cationic surfactant. In basic solution prepared with sodium hydr

Abstract Gemini‐type cationic surfactants containing carbonate linkages as biodegradable and chemically recyclable segments, consisting of two long‐chain alkyl groups, two quaternary ammonium groups and a linker moiety, were designed and synthesized as novel green and sustainable cationics with improved physicochemical and biological activities. The gemini‐type cationics containing a carbonate linkage showed lower critical micelle concentration values compared to the corresponding single‐type ca

Abstract Novel gemini‐type cationics containing carbonate linkages as biodegradable and chemically recyclable segments were designed and synthesized by a green process. The carbonate linkages were introduced into only the hydrophobic moiety or in both the hydrophobic and linker moieties of gemini‐type cationics. They showed higher surface activities, such as a low critical micelle concentration value, a surface tension lowering, and a high adsorption efficiency, when compared to the correspondin

We demonstrate the phototactic behavior of self-propelled micrometer-sized oil droplets in the presence of azobenzene-containing surfactants. These droplets respond sensitively to UV light irradiation due to a variation in the interfacial tension at the droplet surface induced by the molecular conversion of the azobenzene-containing surfactants.

The self-propelled motion with deformation of micrometer-sized soft matter in water has potential application not only for underwater carriers or probes in very narrow spaces but also for understanding cell locomotion in terms of non-equilibrium physics. As far as we know, there have been no reports about micrometer-sized self-propelled soft matter mimicking amoeboid motion underwater. Here, we report an artificial molecular system of underwater oil droplets exhibiting self-propelled motion with

Micrometer-sized self-propelled oil droplets in nonequilibrium systems have attracted much attention, since they form stable emulsions composed of oil, water, and surfactant which represent a primitive type of inanimate chemical machinery. In this work, we examined means of controlling the movement of oil droplets by studying the dynamics of n-heptyloxybenzaldehyde droplets in phosphate buffers containing alkanediyl-α,ω-bis(N-dodecyl-N,N-dimethylammonium bromide) (nG12) with either tetramethylen

Self-propelled motion of micrometer-sized oil droplets in surfactant solution has drawn much attention as an example of nonlinear life-like dynamics under far-from-equilibrium conditions. The driving force of this motion is thought to be induced by Marangoni convection based on heterogeneity in the interfacial tension at the droplet surface. Here, to clarify the required conditions for the self-propelled motion of oil droplets, we have constructed a chemical system, where oil droplet motion is i

Micrometer-sized self-propelled oil droplets under a far-from-equilibrium condition have drawn much attention because of their potential as a dynamic model for the chemical machinery in living organisms. To clarify the effect of interactions between the system components (surfactant, oil, and water) on the locomotion mode of droplets, we investigated the behaviors of oil droplets composed of n-heptyloxybenzaldehyde (HBA) in solutions of cationic surfactants having or not having an ester or an et

Novel biodegradable and chemically recyclable carbonate-type cationic surfactants consisting of a long chain alkyl group and a quaternary ammonium propyl group were designed and synthesized as a green surfactant. These carbonate-type cationics showed better surface activities in an aqueous solution when compared to the conventional cationics. Novel cationics containing both the carbonate linkage and n-dodecyl group showed strong antimicrobial properties, enzymatic degradabilities for chemical re

Unique dynamics using inanimate molecular assemblies based on soft matter have drawn much attention for demonstrating far-from-equilibrium chemical systems. However, there are no soft matter systems that exhibit a possible pathway linking the self-propelled oil droplets to formation of giant vesicles stimulated by low pH. In this study, we conceived an experimental oil-in-water emulsion system in which flocculated particles composed of a imine-containing oil transformed to spherical oil droplets

We demonstrate a novel system that exhibits both self-propelled motion and division of micrometer-sized oil droplets induced by chemical conversion of the system components. Such unique dynamics were observed in an oil-in-water emulsion of a benzaldehyde derivative, an alkanol and a cationic surfactant at a low pH.

Unique dynamics using inanimate molecular assemblies have drawn a great amount of attention for demonstrating prebiomimetic molecular systems. For the construction of an organized logic combining two fundamental dynamics of life, we demonstrate here a molecular system that exhibits both division and self-propelled motion using oil droplets. The key molecule of this molecular system is a novel cationic surfactant containing a five-membered acetal moiety, and the molecular system can feed the self

Various amphiphiles including surfactants and lipids have been designed and synthesized to improve and create new functionalities. In particular, the emergence of cell-like behaviors of giant vesicles (GVs) composed of synthetic lipids has drawn much attention in the development of chemical models for cells. The aim of this study was to measure temperature-dependent morphological changes of GVs induced by fragmentation and subsequent growth using hydrolysable cationic lipids having an amide link

Chemistry has a key role to play in maintaining and improving our quality of life, such as in medicine, materials and electronics. However, it has also caused damage to human health and the natural environment. To make chemistry compatible with human health and the environ‐ ment, Anastas and Warner have proposed 12 principles of green chemistry, which help to explain what it means in practice [1]. The principles cover a wide range of concepts, such as the molecular design and synthetic routes of

Abstract The movement of supramolecular self‐assemblies has been induced by the application of external stimuli that cause a shift to non‐equilibrium conditions. However, few supramolecular chemical systems exist in which multiple different functions are associated with movement. Herein, we observed multiple phase transition of micrometer‐sized lauronitrile oil droplets in a solution of cationic surfactants with aniline skeletons in the presence of metal ions. These dynamics include tactic motio