Journal of the Japan Society of Colour Material
Online ISSN : 1883-2199
Print ISSN : 0010-180X
ISSN-L : 0010-180X
Volume 85, Issue 9
Displaying 1-6 of 6 articles from this issue
Original Technical Paper
  • Toshihiro ISHII, Kazuaki HASHIMOTO
    2012 Volume 85 Issue 9 Pages 357-364
    Published: September 15, 2012
    Released on J-STAGE: December 20, 2012
    JOURNAL FREE ACCESS
    Carbon nanotubes (CNTs) possess various qualities such as outstanding brightness, strength, conductivity, heat conduction, and the ability to emit electrons. In general, such characteristics can be expressed by dispersing a CNT material into a solvent. However, CNTs cannot be dispersed easily because their aggregates are very hard. In the experiment described in this study, we used a bead mill and an ultrasonic homogenizer to mechanically disperse CNTs into a solvent. The devices were used to disperse multi-wall carbon nanotubes (MWCNT) into a solvent. To evaluate the dispersion efficiency of the bead mill, we examined the relation among dispersion time, specific energy, and median diameter (X50) of MWCNTs obtained through dispersion under different conditions. The results indicated that the dispersion efficiency of MWCNTs varies, depending on the operating conditions. In addition, by using a specific energy, it was demonstrated that the diameter of the beads exerts a great effect on dispersion efficiency. A comparison of the bead mill and ultrasonic homogenizer showed that the shape and hardness of the initial MWCNT's aggregates have an effect on the dispersion efficiency.
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Digest
  • Rie KAKEHASHI
    2012 Volume 85 Issue 9 Pages 365-369
    Published: September 15, 2012
    Released on J-STAGE: December 20, 2012
    JOURNAL FREE ACCESS
    Amphiphilic substances form various types of aggregate structures depending on their molecular structures and solution conditions. The aggregate structures affect solution properties. For example, the viscosity of aqueous micellar solutions depends on the size and shape of the aggregates. Therefore, the control of aggregate structures corresponds to control of the solution properties. Some intermolecular interactions, such as electrostatic interactions and hydrogen bonding between surfactant molecules, can be used to control aggregate structures. In the present paper, cationic and anionic surfactant mixed systems and amine oxide surfactants systems are described. Cationic and anionic surfactant mixed systems are typical examples of systems that can be used to control electrostatic interactions between molecules. On the other hand, amine oxide surfactant systems have remarkable and different effects on solution properties, such as the critical micelle concentration and the aggregate number of micelles, due to the hydrogen bonding between protonated and deprotonated species.
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Review
  • Tomokazu YOSHIMURA
    2012 Volume 85 Issue 9 Pages 370-377
    Published: September 20, 2012
    Released on J-STAGE: December 20, 2012
    JOURNAL FREE ACCESS
    Recently, we pay attention to trimeric surfactants with three alkyl chains and three quaternary ammonium headgroups in a molecule, and have been researching. Only a few reports are available with regard to research on trimeric surfactants. This review describes design and synthesis, properties such as critical micelle concentration and surface tension, etc., and nanostructures of micelles formed in aqueous solution for star-type cationic trimeric surfactants with tris(2-aminoethyl)amine in spacer and linear-type cationic trimeric surfactants with flexible spacers such as ethylene and propylene, and rigid spacers such as trans-butenylene and m- and p-xylylene.
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  • Satoru HASHIMOTO
    2012 Volume 85 Issue 9 Pages 378-383
    Published: September 20, 2012
    Released on J-STAGE: December 20, 2012
    JOURNAL FREE ACCESS
    Amphiphilic substances such as bio lipids and surfactants having self-organization property form molecular assemblies (self-organized assemblies) with geometric structures related with the critical packing parameter (CPP) of each molecule in the aqueous phase. These self-assemblies have high internal phase ratio emulsification property, enhancing effect on skin penetration of actives, skin moisturizing effect and improvement effect on skin condition. Therefore these self-assemblies can be successfully used for manufacturing highly functional cosmetics and external drugs.
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Serial Lecture
  • Takuji MASUNAGA
    2012 Volume 85 Issue 9 Pages 384-388
    Published: September 20, 2012
    Released on J-STAGE: December 20, 2012
    JOURNAL FREE ACCESS
    Cosmetics need to possess a high level of quality and safety as well as high-functionality responding to consumers' demands, since they are consumer products contributing to quality of life. Nanomaterials, including ultrafine titanium dioxide, have been used to improve the function of cosmetics. Recently, the research concerning the application and safety assessment of nanomaterial has progressed rapidly. Japan Cosmetic Industry Association (JCIA) has conducted original research related to safety of nanomaterials formulated in cosmetics so that the consumer can use them with no safety concerns. This article describes the activities in JCIA regarding safety research on nanomaterials, including the survey on the actual usage of nanomaterials in cosmetics, analysis of the state of nanomaterials present on the skin and toxicological assessment of nanomaterials.
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Serial Lecture
  • Akira NAKAJIMA
    2012 Volume 85 Issue 9 Pages 389-394
    Published: September 20, 2012
    Released on J-STAGE: December 20, 2012
    JOURNAL FREE ACCESS
    Solid surfaces can be classified into three categories: ideal surfaces, well-defined surfaces and real surfaces. Well-defined surfaces are important as criteria in experimental approaches in surface science, and characteristics of real surfaces are extremely important for the design of practical surface function in industrial applications. Various relaxations and atom adsorptions occur on real surfaces, with their degrees depending on chemical composition, bonding nature, crystallographic orientation and crystallinity. This paper presents general information related to solid surface characteristics from the viewpoint of structural and chemical compositions. Subsequently, characteristics of inorganic and organic materials' real surfaces are also described.
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