Synchrotron Small-Angle X-Ray Scattering and Small-Angle Neutron Scattering Studies of Nanomaterials

Takeno, H.

doi:10.1007/978-3-662-48606-1_13

Cited by 9 publications

(7 citation statements)

References 169 publications

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“…Assuming that the interference effects between clay platelets are negligible for a very dilute clay dispersion, the scattering intensity I ( q ) is expressed by I(q) =nclayVclay2Δρ2P(q) where n clay and ∆ ρ are the number density of a clay platelet with a volume of V clay and the scattering contrast factor, respectively. Here P ( q ) represents the form factor of randomly distributed cylindrical particles with the radius R and thickness 2 H [16,17] Pfalse(qfalse)=4true∫0π/2 [sin2(qHcosβ)(qHcosβ)2][J12(qRsinβ)(qRsinβ)2]sinβdβ where J 1 is the Bessel function of the first order, and β represents the angle between q and the axis of the disk. Figure 1 depicts SAXS curves for dilute clay aqueous solutions, (a) a 0.3 wt % laponite solution and (b) a 0.3 wt % sumecton solution.…”

Section: Resultsmentioning

confidence: 99%

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Mechanical Properties and Structures of Clay-Polyelectrolyte Blend Hydrogels

Takeno

Nagai

2018

Gels

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Our recent studies have shown that the hydrogels prepared by blending clay, a dispersant of clay, and a polyelectrolyte (sodium polyacrylate (PAAS)) possess excellent mechanical properties. In order to clarify the mechanism of the toughness, we have so far investigated the effects of the composition, molecular mass of the polymer, and kinds of polymers on the mechanical properties. This study has focused upon the mechanical properties and structures of the clay/PAAS gels using three kinds of smectite clay minerals such as synthetic hectorite (laponite XLG), saponite (sumecton-SA), montmorillonite (kunipia-F), whose particle size becomes larger according to the sequence. Laponite/PAAS and sumecton/PAAS gels were quite tough for high compression, whereas kunipia-F/PAAS did not gelate. In comparison between sumecton/PAAS gel and laponite/PAAS gel, the mechanical property of the former gel was poorer than that of the latter gel due to the inhomogeneous distribution of clay platelets in the gel. Synchrotron small-angle X-ray scattering experiments revealed that their clay platelets laid down in the stretching direction under elongation. Furthermore, it was found that sumecton/PAAS gel under elongation was arranged with an interparticle distance of ~6.3 nm in the direction perpendicular to the stretching. Such local ordering under elongation may originate in local aggregation of sumecton platelets in the original state without elongation.

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Section: Resultsmentioning

confidence: 99%

“…Namely, we can clearly see the structure of the clay platelets from the SAXS intensity of the gel. This is because the clay platelets are composed of heavier atoms, which have larger X-ray scattering length [17]. Figure 6 depicts two-dimensional patterns for laponite/PAAS and sumecton/PAAS gels during elongation.…”

Section: Resultsmentioning

confidence: 99%

Mechanical Properties and Structures of Clay-Polyelectrolyte Blend Hydrogels

Takeno

Nagai

2018

Gels

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“…The scattering profiles for both hydrogels were similar except for the scattering behavior at small q. This result suggests that their scattering curves were significantly dominated by the scattering from ac-SiO 2 nanoparticles constituted of heavy atoms; heavier atoms have a larger scattering length in X-ray scattering [ 33 ].…”

Section: Resultsmentioning

confidence: 98%

Robust and Highly Stretchable Chitosan Nanofiber/Alumina-Coated Silica/Carboxylated Poly (Vinyl Alcohol)/Borax Composite Hydrogels Constructed by Multiple Crosslinking

Takeno

Suto

2021

Gels

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We investigated the mechanical and structural properties of composite hydrogels composed of chitosan nanofiber (ChsNF), positively charged alumina-coated silica (ac-SiO2) nanoparticles, carboxylated poly (vinyl alcohol) (cPVA), and borax. ChsNF/cPVA/borax hydrogels without ac-SiO2 exhibited high Young’s modulus but poor elongation, whereas cPVA/ac-SiO2/borax hydrogels without ChsNF had moderate Young’s modulus but high elongation. ChsNF/ac-SiO2/cPVA/borax hydrogels using both ChsNF and ac-SiO2 as reinforcement agents exhibited high extensibility (930%) and high Young′s modulus beyond 1 MPa at a high ac-SiO2 concentration. The network was formed by multiple crosslinking such as the complexation between borate and cPVA, the ionic complexation between ac-SiO2 and cPVA, and the hydrogen bond between ChsNF and cPVA. Structural analysis by synchrotron small-angle X-ray scattering revealed that the nanostructural inhomogeneity in ChsNF/ac-SiO2/cPVA/borax hydrogel was suppressed compared to those of the ChsNF/cPVA/borax and cPVA/ac-SiO2/borax hydrogels.

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“…However, the results for o -xylene gel are completely different. The absence of crystalline peaks suggested that the gel fibers were amorphous. , …”

Section: Resultsmentioning

confidence: 99%

“…The peak indexations are gathered in Table 2, and the dspacing values have been calculated using the first-order absence of crystalline peaks suggested that the gel fibers were amorphous. 47,48 Organogel Structure and Mechanical Properties Relationship. The macroscopic properties of a heterogeneous material highly depend on the local mechanical properties and structure at various scales.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Effect of Solvent on the Mechanical and Structural Properties of N-Alkyldiamide Organogels

et al. 2021

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Here, we study organogels prepared thanks to a new organogelator, the N-oleyldiamide molecule, which shows a remarkable propensity to gelify a large scope of solvents, from aprotic to high protic solvents. The solvent plays a key role in the formation and stability of supramolecular self-assemblies. However, the understanding and the control of its effects can be complex as many parameters are a priori involved. This study aims to understand the effect of solvent on the structures of organogels and on their final mechanical properties. Five solvent classes have been selected ranking from low protic to high protic, according to the Hansen H-bond parameter δh. The solvent proticity appears to be one of the main parameters that affect the organogel internal structure and therefore the final rheological properties. For a given organogelator fraction, the terminal elastic modulus measured by oscillatory rheology is observed to increase significantly with the Hansen H-bond solvent parameter δh. Materials of different mechanical properties are then shown to display various structures, which are investigated thanks to cryo-SEM. Besides, wide-angle X-ray scattering (WAXS) has been used to probe the gelator organization at the molecular scale with regard to the solvent nature, to understand the supramolecular self-assembly of this promising molecule.

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Synchrotron Small-Angle X-Ray Scattering and Small-Angle Neutron Scattering Studies of Nanomaterials

Cited by 9 publications

References 169 publications

Mechanical Properties and Structures of Clay-Polyelectrolyte Blend Hydrogels

Mechanical Properties and Structures of Clay-Polyelectrolyte Blend Hydrogels

Robust and Highly Stretchable Chitosan Nanofiber/Alumina-Coated Silica/Carboxylated Poly (Vinyl Alcohol)/Borax Composite Hydrogels Constructed by Multiple Crosslinking

Effect of Solvent on the Mechanical and Structural Properties of N-Alkyldiamide Organogels

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