Research into polymer/clay nanocomposites has generally shown that virtually all types and classes of nanocomposites lead to new and improved properties, such as increased mechanical properties, decreased moisture absorption, flammability, and permeability, when compared with their microand macrocomposite counterparts.[1±18] However, seldom have studies been reported on the preparation and characterization of exfoliated poly(ethylene terephthalate) (PET)/clay nanocomposites. The bottleneck in the preparation of these nanocomposites is how to exfoliate the clay uniformly throughout the polymer matrix into individually layered silicates. For the preparation of nanocomposites, it has been shown that hydrophilic or hydrophobic swelling agents, such as longchain organic cations and water-soluble oligomers, can be intercalated or absorbed between adjacent silicate layers. The modified agents or surfactants increase not only the interlayer spacing but also the compatibility, so that polymer chains can be included between the silicate layers during polymerization of the polymer matrix. However, PET/clay nanocomposites could not be exfoliated into individual layers by these traditional methods because there is no driving force provided that facilitates absorption of the monomers or oligomers between adjacent silicate layers during the polymerization process. Related studies emphasize the compatibility between the interfaces of clay and polyester, [19,20] but overlook the factor of the monomer diffusing into the interlayer in order to proceed with polymerization. This conventional treatment causes the PET/clay nanocomposites to become only an intercalated dispersion of clay instead of an exfoliated dispersion in the polymer substrate. To overcome this above-mentioned problem, in this study we apply a catalyst intercalated between the gallery spaces of the clay, and combine it with a novel polymerization process to proportionally disperse the stratiform inorganic mineral materials in the polyester and thus form exfoliated PET/clay nanocomposites.This study applies the catalyst precursor antimony acetate Sb(OAc) 3 as an intercalant after a novel polymerization process, which is described in the experimental section, to disperse the stratiform inorganic mineral materials proportionally in the PET and form nanocomposites. When the purified clays are treated with antimony acetate [Sb(OAc) O]; therefore the negative charges are distributed on the octahedral layers. When PK-805 was intercalated with Sb(OAc) 3 , the strength of the ionic bonds between the clay layers and Sb(OAc) 3 was stronger than those ionic bonds formed between PK-802/CWC and Sb(OAc) 3 . These Sb(OAc) 3 -treated clays were melt mixed with terephthalic acid bis(2-hydroxyethylester) (BHET) and then measured by X-ray diffraction (XRD), the d-spacings are 21.42, 18.18, and 16.53 for PK-802, PK-805, and CWC, respectively. Apparently, BHET is capable of entering the interlayer of the clay to cause swelling.In order to compare the influence of the d-spacing of modif...
The topological Hall effect (THE) has been discovered in ultrathin SrRuO3 (SRO) films, where the interface between the SRO layer and another oxide layer breaks the inversion symmetry resulting in the appearance of THE. Thus, THE only occurs in ultrathin SRO films of several unit cells. In addition to employing a heterostructure, the inversion symmetry can be broken intrinsically in bulk SRO by introducing defects. In this study, THE is observed in 60‐nm‐thick SRO films, in which defects and lattice distortions are introduced by helium ion irradiation. The irradiated SRO films exhibit a pronounced THE in a wide temperature range from 5 to 80 K. These observations can be attributed to the emergence of Dzyaloshinskii–Moriya interaction as a result of artificial inversion symmetry breaking associated with the lattice defect engineering. The creation and control of the THE in oxide single layers can be realized by ex situ film processing. Therefore, this work provides new insights into the THE and illustrates a promising strategy to design novel spintronic devices.
We establish theoretically that in nonmagnetic semiconducting bilayer or multilayer thin film systems rolled up into compact quasi-one-dimensional nanoarchitectures, the ballistic magnetoresistance is very anisotropic: conductances depend strongly on the direction of an externally applied magnetic field. This phenomenon originates from the curved open geometry of rolled-up nanotubes, which leads to a tunability of the number of quasi-one-dimensional magnetic subbands crossing the Fermi energy. The experimental significance of this phenomenon is illustrated by a sizable anisotropy that scales with the inverse of the winding number, and persists up to a critical temperature that can be strongly enhanced by increasing the strength of the external magnetic field or the characteristic radius of curvature, and can reach room temperature.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.