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The existence of ion-clusters in ethylene-acrylic acid copolymers (mole% of acrylic acid is 9.3) neutralized with manganese(II) and nickel(II) acetates, respectively, was studied by dielectric measurements in the temperature range of −180 to 80 °C at several frequencies between 30 Hz and 100 kHz. Theβ′ relaxation due to a micro-Brownian molecular motion aboveT g and theγ relaxation due to a local molecular motion belowT g were observed. Variation in the magnitude and the relaxation temperature of the two relaxations with degree of neutralization by manganese/nickel acetate suggest the formation of ion-clusters in the higher degrees of neutralization above a value between 3.3 and 14% for the Mn(II) salts and above about 14% for the Ni(II) salts. Furthermore, this formation of ion-clusters was evidenced by electron spin resonance and small angle X-ray scattering studies. The ESR spectra for the Mn(II) salts exhibited six peaks at 14% of degree of neutralization and one peak at 62%. This indicates the existence of ion-clusters at 62%. The small angle X-ray scatterings suggested the existence of ion-clusters of diameter of about 27 Å for the Mn(II) salts and 19–23 A for the Ni(II) salts, at the high degrees of neutralization above 14%.

 A series of new ionogenic liquid crystalline (LC) copolymers (A4CB-AA) was prepared by radical copolymerization of 4-(4-cyanobiphenyl-4′-yloxy) butyl acrylate (A4CB) and acrylic acid (AA). The presence of the AA units do not prevent the development of the nematic phase, which is typical of the initial cyanobiphenyl homopolymer. At a content of AA of 42–52 mol%, the copolymers produce the S Ad type of mesophase, and this phenomenon is explained by an increased rigidity of the main chain due to the development of intramolecular hydrogen bonds. By increasing the concentration of AA units higher than 55 mol%, the development of mesophase is prevented, and the as-received copolymers are amorphous. A crucial role of intramolecular hydrogen bonds for the development of the S A phase in the copolymers is proved by synthesizing and studying the copolymers, in which the same type of the mesogenic group A4CB is preserved but the second component is provided by methyl ether of acrylic acid; such copolymers are able to produce only a nematic phase. Studying orientation of LC A4CB-AA copolymers in the magnetic field by the method of wide-line 1H NMR spectroscopy allows one to calculate the temperature dependences of order parameter S and to advance a correct interpretation of experimental data.

Estimation of the number of unit charges per primary particle in aged AgI sols or -suspensions shows that there is no reason to mistrust the applicability of “continuum condensor” double layer models.

Submicron hollow spheres are an interesting class of materials that receive significant attention nowadays. Closed and mechanically robust homogeneous hollow titania microspheres with as much shell thickness as 130 nm were fabricated by coating polystyrene beads with titania nanoparticles using sol–gel chemistry and subsequently removing the core either via heating or a chemical dissolution process. The thickness of the titania shell deposited on polystyrene core was finely tuned between 100 and 130 nm by varying the concentration of titania precursor, i.e., Ti(OEt)4 salt from 0.5 to 2 mM during the coating process. The obtained hybrid core–shell particles and hollow microspheres were characterized by scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, X-ray diffraction, and thermo-gravimetric analysis. The approach employed is well suited to the preparation of titania-coated polystyrene hybrid particles and hollow titania spheres, which can find their applications as novel building blocks with unique optical properties for fabrication of advanced materials, catalyst, and drug delivery system.

Biodegradable tri-component diblock copolymer was synthesized by bulk copolymerization of ε-caprolactone (CL) and D, L-lactide (LA) in the presence of methoxy poly(ethylene glycol) (MePEG), using stannous octoate as catalyst. Their chemical structure and physical properties were investigated by GPC, NMR, DSC, TGAand XRD. The increase of CL/LA ratio in the diblock copolymer leads to lower T g, higher decomposition temperature and crystallinity. Nanoparticles formulated from MePEG–poly(CL-co-LA) (PCAE) possess spherical structure, which was characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The DLS results indicate that the particle size increased with the increase of CL/LA ratio and the hydrophobic fragment length in the copolymer. The drug encapsulation efficiency and the drug release behavior in vitro conditions of camptothecin were measured by high performance liquid chromatography (HPLC). The encapsulation efficiency can be achieved as high as 84.4% and the release behavior can be made well-controlled. MePEG–poly(CL-co-LA) nanoparticles might have a great potential as carriers for hydrophobic drugs.