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208 results on '"Sagisaka, Masanobu"'

26. Fabrication and application of composite adsorbents made by one-pot electrochemical exfoliation of graphite in surfactant ionic liquid/nanocellulose mixtures

Author

Jamaluddin, Nur Amirah, primary, Mohamed, Azmi, additional, Bakar, Suriani Abu, additional, Ardyani, Tretya, additional, Sagisaka, Masanobu, additional, Saito, Haruka, additional, Mamat, Mohamad Hafiz, additional, Ahmad, Mohd Khairul, additional, Abdul Khalil, H. P. S., additional, King, Stephen M., additional, Rogers, Sarah E., additional, and Eastoe, Julian, additional

Published
2021
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31. Highly branched triple-chain surfactant-mediated electrochemical exfoliation of graphite to obtain graphene oxide: colloidal behaviour and application in water treatment

Author

Jamaluddin, Nur Amirah, primary, Mohamed, Azmi, additional, Abu Bakar, Suriani, additional, Ardyani, Tretya, additional, Sagisaka, Masanobu, additional, Suhara, Shota, additional, Hafiz Mamat, Mohamad, additional, Ahmad, Mohd Khairul, additional, King, Stephen M., additional, Rogers, Sarah E., additional, and Eastoe, Julian, additional

Published
2020
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32. Chirality exists in the isotropic liquid above blue phase III.

Author

Yamaguchi, Michiko, Sagisaka, Masanobu, and Yoshizawa, Atsushi

Subjects
*OPTICAL rotation, *CHIRALITY, *LIQUIDS, *PHASE transitions, *LIQUID crystal films, *SURFACE active agents
Abstract

The chirality of spherical liquid crystal droplets was investigated in this study. We report the effect of confinement on blue phase III (BPIII) spheres. We investigated the behaviours of the spherical BPIII droplets under the absence of surfactants or nanoparticles, spherical droplets in water, and polymerised capsules in air. Optical activity was observed between the transparent isotropic liquid phase and the bluish BPIII in the spherical BPIII droplets and capsules. This behaviour was not observed in the spherical cubic BP samples. Optical activities in the isotropic-phase temperature range were specific to BPIII. Furthermore, the phase transition behaviours of BPIII differed based on the sample confinement conditions, even for samples with the same mixture composition. Spherical confinement induced spontaneous microscopic chiral order formation at the isotropic liquid temperature range in the BPIII liquid crystal composition. [ABSTRACT FROM AUTHOR]

Published
2022
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36. Foam Generation and Stability: Role of the Surfactant Structure and Asphaltene Aggregates

Author

Alexander, Shirin, Barron, Andrew R., Denkov, Nikolai, Grassia, Paul, Kiani, Sajad, Sagisaka, Masanobu, Shojaei, Mohammad Javad, and Shokri, Nima

Abstract

Understanding how the surfactant molecular structure affects foam stability is important in various applications, such as soil remediation, the food industry, enhanced oil recovery, and hydraulic fracturing. In this study, we conduct a systematic series of experiments in a Hele–Shaw cell to assess and explain the effect of surfactants on foamability and foam stability in the absence and presence of oil and asphaltene aggregates. Four surfactants with different molecular weights were studied, including three anionic surfactants, sodium 1,5-bis[(1H,1H,2H,2H-perfluorohexyl)oxy]-1,5-dioxopentane-2-sulfonate (FG4), C18H37SO4Na (LSES), and sodium dodecyl sulfate (SDS), and one cationic surfactant (CTAB, (C16H33NMe3)Br). We observed that the higher electrostatic repulsion between the foam film surfaces for the anionic surfactants (FG4 > LSES > SDS) strongly influences the process of foam generation and stability when compared with the cationic surfactant (CTAB). For example, the foam coarsening rate for CTAB was 700% higher than that for FG4 when we performed experiments in an empty Hele–Shaw cell. Furthermore, the foam experiments performed in the presence of oil revealed maximum long-term stability and minimum bubble coarsening for the partially fluorinated FG4 surfactant. The experiments in the presence of asphaltene–oil mixtures revealed that the latter has a detrimental effect on foam stability, except for FG4. The foam experiments clearly show the significance of the subtle interactions between the surfactant headgroup charge, chain length, and branching. The obtained results could be useful in designing appropriate surfactants for foam stabilization in various applications.

Published
2022
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38. Disclination network morphologies in blue phase III.

Author

Yamaguchi, Michiko, Shimizu, Kenji, Sagisaka, Masanobu, and Yoshizawa, Atsushi

Subjects
DISCLINATIONS, POLYMER networks, LIQUID crystals, POLYMER liquid crystals, SCANNING electron microscopy
Abstract

We prepared some blue phase (BP) materials with different concentrations of reactive monomers. They exhibited a cubic blue phase (cubic BP) or blue phase III (BPIII). We obtained their polymer-stabilised cubic BP and BPIII liquid crystals using photo-polymerisation. The temperature ranges of both BPs widened with increasing monomer concentration. After removing the low-molecular-weight materials, we observed the remaining polymer networks using field-emission scanning electron microscopy (SEM). We investigated the relationship between the polymer-stabilised BP (PS-BP) temperature range and polymer network morphology. The polymer network derived from the non-stabilised PS-BPIII exhibited µm-sized pores. Increasing the monomer concentration, the BPIII temperature range widened from 13 K to more than 49 K and the pore size dramatically decreased from several µm to about 100 nm. On the other hand, periodic nanoporous structures were partially observed even for the PS-cubic BP. The nanoporous structures were spread to the whole area for the PS-cubic BP with a wide BP temperature range. Furthermore, we discuss how the polymer network stabilises BPIII. [ABSTRACT FROM AUTHOR]

Published
2021
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42. Rational design of aromatic surfactants for graphene/natural rubber latex nanocomposites with enhanced electrical conductivity

Author

Mohamed, Azmi, primary, Ardyani, Tretya, additional, Abu Bakar, Suriani, additional, Sagisaka, Masanobu, additional, Umetsu, Yasushi, additional, Hamon, J.J., additional, Rahim, Bazura Abdul, additional, Esa, Siti Rahmah, additional, Abdul Khalil, H.P.S., additional, Mamat, Mohamad Hafiz, additional, King, Stephen, additional, and Eastoe, Julian, additional

Published
2018
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43. Fourier transform infrared spectroscopic study of water-in-supercritical C[O.sub.2] microemulsion as a function of water content

Author

Takebayashi, Yoshihiro, Mashimo, Yasuaki, Koike, Daisuke, Yoda, Satoshi, Furuya, Takeshi, Sagisaka, Masanobu, Otake, Katsuto, Sakai, Hideki, and Abe, Masahiko

Subjects
Fourier transform infrared spectroscopy -- Research, Carbon dioxide -- Research, Water chemistry -- Research, Chemicals, plastics and rubber industries
Abstract

Fourier transform infrared (FT-IR) spectrum of water-in-supercritical C[O.sub.2] (W/scC[O.sub.2]) microemulsion was used to study the distribution of water into C[O.sub.2], interfacial area around surfactant headgroup and core water pool. The results indicated that water was introduced preferentially into C[O.sub.2] and the interfacial area at small water content followed by loading into the micelle core after the saturation of C[O.sub.2] with water and the full hydration of the surfactant headgroup.

Published
2008

46. Water-in-CO2Microemulsions Stabilized by an Efficient Catanionic Surfactant

Author

Sagisaka, Masanobu, Saito, Tatsuya, Abe, Masashi, Yoshizawa, Atsushi, Blesic, Marijana, Rogers, Sarah E., Alexander, Shirin, Guittard, Frédéric, Hill, Christopher, and Eastoe, Julian

Abstract

To facilitate potential applications of water-in-supercritical CO2microemulsions (W/CO2μEs) efficient and environmentally responsible surfactants are required with low levels of fluorination. As well as being able to stabilize water–CO2interfaces, these surfactants must also be economical, prevent bioaccumulation and strong adhesion, deactivation of enzymes, and be tolerant to high salt environments. Recently, an ion paired catanionic surfactant with environmentally acceptable fluorinated C6tails was found to be very effective at stabilizing W/CO2μEs with high water-to-surfactant molar ratios (W0) up to ∼50 (Sagisaka, M.; et al. Langmuir2019, 35, 3445−3454). As the cationic and anionic constituent surfactants alone did not stabilize W/CO2μEs, this was the first demonstration of surfactant synergistic effects in W/CO2microemulsions. The aim of this new study is to understand the origin of these intriguing effects by detailed investigations of nanostructure in W/CO2microemulsions using high-pressure small-angle neutron scattering (HP-SANS). These HP-SANS experiments have been used to determine the headgroup interfacial area and volume, aggregation number, and effective packing parameter (EPP). These SANS data suggest the effectiveness of this surfactant originates from increased EPP and decreased hydrophilic/CO2-philic balance, related to a reduced effective headgroup ionicity. This surfactant bears separate C6F13tails and oppositely charged headgroups, and was found to have a EPP value similar to that of a double C4F9-tail anionic surfactant (4FG(EO)2), which was previously reported to be one of most efficient stabilizers for W/CO2μEs (maximum W0= 60–80). Catanionic surfactants based on this new design will be key for generating superefficient W/CO2μEs with high stability and water solubilization.

Published
2020
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47. Preparation of multiwall carbon nanotubes (MWCNTs) stabilised by highly branched hydrocarbon surfactants and dispersed in natural rubber latex nanocomposites

Author

Massachusetts Institute of Technology. Department of Chemical Engineering, Brown, Paul, Mohamed, Azmi, Anas, Argo Khoirul, Abu Bakar, Suriani, Aziz, Azira Abd., Sagisaka, Masanobu, Eastoe, Julian, Kamari, Azlan, Hashim, Norhayati, Isa, Illyas Md, Massachusetts Institute of Technology. Department of Chemical Engineering, Brown, Paul, Mohamed, Azmi, Anas, Argo Khoirul, Abu Bakar, Suriani, Aziz, Azira Abd., Sagisaka, Masanobu, Eastoe, Julian, Kamari, Azlan, Hashim, Norhayati, and Isa, Illyas Md

Abstract

The performance of single-, double- and triple-chain anionic sulphosuccinate surfactants for dispersing multiwall carbon nanotubes (MWNCTs) in natural rubber latex (NR-latex) was studied using a range of techniques, including field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Raman spectroscopy. The conductivities of the nanocomposites were also investigated using four-point probe measurements. Here, MWCNTs were efficiently dispersed in NR-latex with the aid of hyperbranched tri-chain sulphosuccinate anionic surfactants, specifically sodium 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate (TC14). This paper highlights that TC14 performs much better than that of the commercially available surfactant sodium dodecyl sulphate (SDS), demonstrating how careful consideration of surfactant architecture leads to improved dispersibility of MWCNTs in NR-latex. The results should be of significant interest for improving nanowiring applications suitable for aerospace-based technology., Malaysia Toray Science Foundation (Grant 2012-0138-102-11), National Nanotechnology Directorate Division (Research Grant 2014-0015-102-03), Universiti Pendidikan Sultan Idris (Research Grant 2012-0113-102-01), Malaysia. Ministry of Education (Research Acculturation Grant Scheme. Grant 2013-0001-101-72), JEOL Ltd.

Published
2016

48. Low surface energy materials with non-bioaccumulative potential

Author

El-Maiss, Janwa, Darmanin, Thierry, Eastoe, Julian, Sagisaka, Masanobu, Guittard, Frédéric, Surfaces & Interfaces, Laboratoire de physique de la matière condensée (LPMC), Centre National de la Recherche Scientifique (CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), School of Chemistry, University of Bristol [Bristol], Department of Frontier Materials Chemistry, Graduate School of Science and Technology, and Hirosaki University-Hirosaki University

Subjects
[CHIM.MATE]Chemical Sciences/Material chemistry
Published
2014

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