The aggregation behaviors of a Gemini surfactant [C12H25(CH3)2N(+)(CH2)2N(+)(CH3)2C12H25]Br2(-) (12-2-12) in two protic ionic liquids (PILs), propylammonium nitrate (PAN) and butylammonium nitrate (BAN), were investigated by means of several experimental techniques including small and wide-angle X-ray scattering, the polarized optical microscopy and the rheological measurement. Compared to those in ethylammonium nitrate (EAN), the minor structural changes with only one or two methylene units (-CH2-) increase in cationic chain length of PIL, result in a dramatic phase transition of formed aggregates. The critical micellization concentration was increased in PAN, while no micelle formation was detected in BAN. A normal hexagonal phase was observed in the 12-2-12/PAN system, while the normal hexagonal, bicontinuous cubic, and lamellar phases were mapped in the 12-2-12/BAN system. Such aggregation behavior changes can be ascribed to the weaker solvophobic interactions of 12-2-12 in PAN and BAN. The unique molecular structure of 12-2-12 is also an important factor to highlight such a dramatic phase transition due to the PIL structure change.
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Nano Lett
January 2025
Key Laboratory of Materials Physics, Institute of Solid State Physics, Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences, Hefei, Anhui 230031, China.
Two-dimensional (2D) room-temperature chiral multiferroic and magnetic topological materials are essential for constructing functional spintronic devices, yet their number is extremely limited. Here, by using the chiral and polar HPP (HPP = 4-(3-hydroxypyridin-4-yl)pyridin-3-ol) as an organic linker and transition metals (TM = Cr, Mo, W) as nodes, we predict a class of 2D TM(HPP) organometallic nanosheets that incorporate homochirality, room-temperature magnetism, ferroelectricity, and topological nodes. The homochirality is introduced by chiral HPP linkers, and the change in structural chirality induces a topological phase transition of Weyl phonons.
View Article and Find Full Text PDFACS Nano
January 2025
WA School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Perth, WA 6102, Australia.
Quadruple perovskite oxides have received extensive attention in electronics and catalysis, owing to their cation-ordering structure and intriguing physical properties. However, their repertoires still remain limited. In particular, piezoelectricity from quadruple perovskites has been rarely reported due to the frustrated symmetry-breaking transition in A-site-ordered perovskite structures, disabling their piezoelectric applications.
View Article and Find Full Text PDFSymmetry-breaking spin-state transitions in two of three isostructural salts of MnIII spin-crossover cations, [MnIII(3-OMe-5-NO2-sal2323)]+, with heavy anions are reported. The ReO4- salt undergoes two-step spin crossover which is coupled with a re-entrant symmetry-breaking structural phase transition between a high temperature phase (S = 2, C2/c), an intermediate ordered phase (S = 1/S = 2, P21/c), and a low temperature phase (S = 1, C2/c). The AsF6- complex undergoes an abrupt transition between a high temperature phase (S = 2, C2/c) and a low temperature ordered phase (S = 1/S = 2, P-1).
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Hangzhou Institute of Medicine, Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China.
Biomolecular condensation lays the foundation of forming biologically important membraneless organelles, but abnormal condensation processes are often associated with human diseases. Ribonucleic acid (RNA) plays a critical role in the formation of biomolecular condensates by mediating the phase transition through its interactions with proteins and other RNAs. However, the physicochemical principles governing RNA phase transitions, especially for short RNAs, remain inadequately understood.
View Article and Find Full Text PDFSmall
January 2025
Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal, 462 066, India.
The structural and electronic changes are investigated in a 3D hybrid perovskite, methylhydrazinium lead chloride (MHyPbCl) from a host/guest perspective as it transitions from a highly polar to less polar phase upon cooling, using first-principles calculations. The two phases vary structurally in the guest (MHy) orientation and the two differently distorted host (lead halide) layers. These findings highlight the critical role of guest reorientation in reducing host distortion at high temperatures, making the former the primary order parameter for the transition, a notable contrast to the case of other hybrid perovskites.
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