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A systematical calculation is performed to explore the equilibrium phase behaviors of linear-dendritic triblock copolymer A B ( 2 g + 1 − 2 ) C 2 g + 1 ( g is the generation number of the block B, and G g is short for A B ( 2 g + 1 − 2 ) C 2 g + 1 ) from G1 to G5 by using self-consistent field theory. Eight phases are found: two-colored lamellar phase, three-colored lamellar phase, hexagonal phase, core shell hexagonal phase, tetragonal phase, core shell tetragonal phase, two interpenetrating tetragonal phase, lamellar phase with beads except disordered phase, by varying the interaction parameters between different blocks, the volume fractions of the blocks and the generation number. While investigating the effect of linear coil length on morphology, we find the longer linear length ( f A = 0.5) for G1, G2 can be beneficial to form the lamellar phase, however, tend to form hexagonal phase easily with generation number increasing from 3 to 5, and short linear length ( f A = 0.2) can be better for inducing hexagonal phase from G1 to G5. It becomes more and more difficult to phase separate with generation number increasing from 1 to 5 due to the architectural complexity. However, increasing the interaction parameters is helpful to facilitate phase separation. It is likely to offer new opportunity for designing nanomaterials and applying to template technology by finely controlling the dendron generations, length of the linear chain, interaction parameters of linear-dendritic triblock copolymers. [ABSTRACT FROM AUTHOR]

ABSTRACT Liquid crystalline block copolymers (LCBCPs) are fascinating for their combining molecular level liquid crystalline orders and microphase separated multidomain morphologies. Here in this article, a series of PEG-containing side-chain discotic LCBCPs of PEG- b- Pm- n with variant spacer length m = 6, 10 and degree of polymerization (DP) of discotic LC block from n = 10 to 45, have been well-synthesized via reversible addition-fragmentation chain-transfer (RAFT) polymerization. The RAFT process mediated by macromolecular chain transfer agent (macroCTA) shows remarkable monomer concentration dependence. The influence of the introduced PEG block on the nano-scale microphase-segregation and mesophase organization is closely related to the side-chain triphenylene (TP) discogens stacking mode dependent on the spacer length. Wherein, the PEG- b- P6- n series with a six-methylene spacer exhibit consistent microphase separation with slightly disturbed yet ordered columnar structures. While for PEG- b- P10- n series with a longer ten-methylene spacer, the columnar organization in the copolymers is even improved in contrast with the low order of randomly TP stacking in their corresponding homopolymers. This work offers a viable and inspiring pathway for controlled synthesis of block copolymers with bulky side groups, as well as enhances in-depth understanding of the hierarchical superstructure organization in discotic units involved complex block copolymers. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 2544-2553 [ABSTRACT FROM AUTHOR]

Abstract: In this paper, based on the synthesis of precursor linear-dendritic block copolymers (LDBCs) with a linear poly(ethylene glycol) (PEG) block of molecular weight around 2000 and dendritic polyamidoamine (PAMAM) segments of generation G0 to G3, a series of azobenzene-containing amphiphilic LDBCs mPEG-dendr[PAMAM-(AZO) n ] (n = 2, 4, 8, 16) have been successfully prepared in moderate yields 45–60%, through complete Michael addition between the peripheral amine groups of dendritic segment and the reactive azobenzene acrylate mesogen units bearing octyloxy tails and flexible decylmethylene spacers. The purified copolymers have been characterized and confirmed by NMR, FT-IR, MALDI-TOF MS, and GPC showing narrow molecular weight distribution in the range 1.09–1.20. A generation-dependent polymeric micellar aggregation behavior of thus obtained amphiphilic LDBCs from nanofibers of uniform diameter around 20 nm to nanospheres/oval sheets, vesicles, and porous large compound micelles (LCMs) of micrometer size has been demonstrated in selective solvent mixture of dioxane/water. Furthermore, photoisomerization transformation of these azobenzene-containing LDBCs and their kinetics of reversible trans-cis-trans photochemical transitions in THF solution have also been investigated, the measured trans-cis photoisomerization rate constant 0.0240 s−1 for G3 copolymer is twice of the 0.0127 s−1 determined for the precursor azobenzene compound, manifesting a kind of promising photoresponsive copolymer materials. [Copyright &y& Elsevier]

Abstract: A series of carboxylic acid functionalized hybrid linear-dendritic block copolymers (LDBCs) derived from methoxy poly(ethylene glycol) (MPEG) and variant generation dendrons from 2,2-bis(hydroxymethyl) propionic acid were synthesized and employed as CaCO3 crystallization growth modifiers. Mainly spherical vaterite particles of gradually reduced sizes were produced with the increase of the polymer additive concentration and/or the dendron segment generation number, while the incorporated polymer organic components in the particles increased for the promoted binding efficiency and ever enhanced adsorption ability. A higher mineralization temperature resulted in significantly larger particle size and partly calcite formation. Under the same molar concentration of carboxylic acid, the same size level particles were obtained which manifested the crucial role of the functional group, meanwhile, the slight decrease of the spherical vaterite diameters with increasing generation number and especially the formation of particular pine-cone shaped calcite crystals also revealed the significant effect of the architectural structure of variant generations and some special characters of the hybrid LDBC structures. [Copyright &y& Elsevier]