Summary: The theory of lamellar superstructures of an ABC 3‐miktoarm star terpolymer in the conditions corresponding to the strong segregation limit for linear ABC triblock terpolymer has been developed. According to the particular molecular topology (namely, the common junction point for all three blocks), the system cannot avoid volume interactions between monomers of different blocks even in this limit. Hence, in the lamellar superstructure, there exists the so‐called “mixed” domain containing monomers of all three blocks but formed mainly of the block with the lowest degree of incompatibility. It is shown that unfavorable volume interactions in this domain are minimized by the increase of the interfacial area per ABC molecule which makes the mixed domain narrow. This leads to an unusual behavior of the period of the superstructure which decreases with an increase in the length of the block with the lowest incompatibility. However, in the case of a “synchronous” increase in the size of the branches of the ABC 3‐miktoarm star terpolymer, the period of the superstructure increases similarly to that for a linear ABC triblock terpolymer.
Mixtures of hydrogenated and fluorinated surfactants are known to form either mixed or segregated micelles: the conclusions are much dependant on the precision of the experimental measurements and on the model used for interpretation. Recently, mixed surfactant solutions were probed at the micellar or molecular level by SANS, fluorescence or NMR. It leads to an intermediate structure for the mixed micelles with an intramicellar segregation of the fluorinated and hydrogenated surfactant.This intramicellar segregation was also observed in a variety of more complex systems which are rapidly surveyed in the second part. 相似文献
Rényi statistical entropy as a means to quantify mixing in two‐dimensional binary systems is presented. The use of Rényi entropies in defining the scale and intensity of segregation for mixing quality determination is analyzed. Finally, the relationship between the mixing process and the structures generated in the system is explored by using the Rényi entropy as an easy and computationally efficient method to calculate the system spectrum of fractal dimensions.
Ti3CNTx MXenes with unique electrical conductivity can be widely applied for supercapacitors and electromagnetic shielding. However, its relatively low-yield quaternary nitrogen-containing Ti3AlCN ceramics precursor (less than 50%), due to the inevitable Al segregation during the synthesizing process, significantly hindered its widely commercial applications. Herein, we employed the controllable AlN-oversaturation precursor strategy to precisely tune the phase transition point of quaternary Ti3AlCN ceramics to obtain high-yield Ti3AlCN precursor for the purpose of high conductivity Ti3CNTx MXenes. Combined energy dispersive X-ray spectrometer (XRD) with X-ray photoelectron spectroscopy (XPS) characterizations, the yield of the quaternary nitrogen-containing Ti3AlCN ceramics was evidently proved to be up to 70%, which is 1.4 times than that of previously reported works. Such relatively high-yield quaternary Ti3AlCN is mainly ascribed to the elimination of Al segregation. Based on it, we further developed accordion-like two-dimensional (2D) MXene via hydrofluoric acid etch and vacuum freeze-dry. This novel accordion-like 2D Ti3CNTx MXene possesses high electrochemical capacitive properties (209 F/g). Therefore, this controllable AlN-oversaturation precursor strategy will pave a way to exploit costly high-yield MAX ceramics precursor for high conductivity MXenes and also play a powerful role in promoting their practical applications including electrical and magnetic engineering fields. 相似文献
