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In this work, the nanostructures and phase diagrams of lamella-forming and cylinder-forming ABC linear triblock copolymers confined in spherical cavities are investigated on the basis of real-space self-consistent field theory. We designate specific monomer-monomer interactions and block composition and study morphology transformation under spherical confinement with a neutral surface. Various potentially valuable morphological structures, such as two- or three-colored spheres, rotational structures, and biconcave disklike structures, are identified in the phase diagrams constructed on confining diameters. Single confinement induces an obvious transformation of self-assembled structures, which still retain some of the conformational properties of bulk structures. We then focus on phase morphology under preferential surfaces. Absorption can smooth out differences in block ratios, and similar structures can be assembled from block copolymers with different proportions. We incorporate a non-centrosymmetric feature into our spherical confinement model and design a Janus adsorption field to explore unpredictable microphase behavior. Results show that the unbalance of the block ratio causes adsorption to exert a stable shaping effect on conformation. The influence of confinement on the degree of freedom of polymer chains disrupts the influence of adsorption on the complexity and transformation activity of self-assembled structures. The theoretical results correspond to recent experimental observations and contribute to the field functional material synthesis. [ABSTRACT FROM AUTHOR]

The morphologies and phase diagrams exhibited by symmetric ABC star triblock copolymer nanoparticles are investigated on the basis of real-space self-consistent field theory. The ABC star triblock copolymers were chosen to be tiling-forming with fixed polymer parameter and the spherical boundaries were modeled using the masking technique. We first study a number of examples where the ABC triblock copolymers confined in spherical cavities with neutral surface. Then, two types of spherical cavity distinct preferential surfaces are considered, including both A-block attractive and repulsive preferential surfaces. We aim at the effects due to various spherical cavity diameters and the degree of interactions between the polymer and the spherical surface. A variety of morphologies, such as ring-like structures, concentric sphere, and irregular cylinder, were identified in phase diagrams. The results show that both the degree of interactions and spherical diameters can influence the formation of morphologies so that ring-like structures and other novel structures could be obtained. [ABSTRACT FROM AUTHOR]

Abstract An actinomycete strain was isolated from a soil sample collected from a secondary forest at Yongsheng of Yunnan province, China. The isolate, YIM 31634T, was identified by a polyphasic approach. The 16S rDNA sequence analysis showed that the strain YIM 31634T belongs to the genus Streptomyces, with closest similarity to Streptomyces olivochromogenes DSM 40451T (97.66% similarity). Sequence similarities between strain YIM 31634T and other Streptomyces species in the same subclade ranged from 97.59% (with Streptomyces resistomycificus DSM 40133T) to 97.22% (with Streptomyces mirabilis ATCC 27447T). Key phenotypic characteristics as well as chemotaxonomic features of the actinomyces were congruent with the description of the genus Streptomyces. On the basis of phenotypic and phylogenetic analyses, strain YIM31634T was recognized as a new species of the genus Streptomyces for which the name Streptomyces roseoalbus sp. nov. is proposed. The strain YIM 31634T has been deposited in the Chinese Center of Type Culture Collection as strain CCTCC M 203016T and in the Deutsche Sammlung von Mikroorganismen (DSM 41833T). [ABSTRACT FROM AUTHOR]