Rod diblock copolymer

Binary Mixture of a Flexible and a Rigid Rod Diblock Copolymer... 

Figure 2. Structure of liquid crystalline block copolymers (LC-BCPs) (A) rod-coil diblock copolymer (B) rod-coil diblock copolymer with flexible spacer in the rod block (C) side group liquid crystal-coil (SGLC- coil) diblock copolymers (D) coil -rod-coil ABC triblock copolymers (predicted to be novel ferroelectric fluid by R. G. Petschek and K. M. Wiefling, Phys. Rev. Lett., 1987, 59(3), 343-346) (E) rod-rod diblock copolymer (one example of well-defined po-ly(n-hexyl isocyanate-fc-n-butyl isocyanate) rod-rod diblock copolymer was given by Novak et al. [68], however, no morphology studies were reported) (F) dendritic liquid crystal-coil (DLC-coil) diblock copolymer (not reported).

X. Pang, L. Zhao, C. Feng, Z. Lin, Novel Amphiphilic Multiarm, Starhke Coil-Rod Diblock Copolymers via a Combination of Click Chemistry with Living Polymerization. Macromolecules 2011,44,7176-7183. 

Figure 11.23 Synthesis of a rod-rod diblock copolymer containing conjugated P3HT and liquid crystalline PBLC by a combination of GRIM and ring-opening polymerization.

Pang X-C, Zhao L, Feng C-W, Lin Z-Q (2011) Novel amphiphilic multiarm, starUke coil-rod diblock copolymers via a combination of click chemistry with living polymerization. Macromolecules 44 7176—7183... 

Minich E.A., Nowak A.P., Deming T.J., and Pochan, D.J. Rod-rod and rod-coil self-assembly and phase behavior of pol3fpeptide diblock copolymers. Polymer, 45, 1951, 2004. 

Influence on the phase behaviour is observed if even small amounts (0.5 wt %) of hairy silica-like nanoparticles obtained by block-copolymer-directed sol-gel synthesis are added to a block copolymer [53,214]. On the example of a PS-fo-PI diblock copolymer a depression of the ODT of approx. 20 K was observed (Fig. 68), accompanied by a broadening of the transition. The largest depression was observed for rod-like nanoparticles, which is explained by the energy introduced by the defects [215]. 

Fig. 10 Schematic representation of the nanoreplication processes from block copolymers, a Growth of high-density nanowires from a nanoporous block copolymer thin film. An asymmetric PS-fc-PMMA diblock copolymer was aligned to form vertical PMMA cylinders under an electric field. After removal of the PMMA minor component, a nanoporous film is formed. By electrodeposition, an array of nanowires can be replicated in the porous template (adapted from [43]). b Hexagonally packed array of aluminum caps generated from rod-coil microporous structures. Deposition of aluminum was achieved on the photooxidized area of the rod-coil honeycomb structure (Taken from [35])...

The potential for novel phase behaviour in rod-coil block copolymers is illustrated by the recent work of Thomas and co-workers on poly(hexyl iso-cyanate)(PHIC)-PS rod-coil diblock copolymers (Chen etal. 1996). PHIC, which adopts a helical conformation in the solid state, has a long persistence length (50-60 A) (Bur and Fetters 1976) and can form lyotropic liquid crystal phases in solution (Aharoni 1980). The polymer studied by Thomas and co-workers has a short PS block attached to a long PHIC block. A number of morphologies were reported—wavy lamellar, zigzag and arrowhead structures—where the rod block is tilted with respect to the layers, and there are different alternations of tilt between domains (Chen et al. 1996) (Fig. 2.37). These structures are analogous to tilted smectic thermotropic liquid crystalline phases (Chen et al. 1996). 

Diblock copolymers of NIPA and EO showed somewhat different behavior [45]. The copolymers were synthesized using NIPA monomer and PEO-containing macroinitiator. The copolymers aggregated at high temperature with no collapse of individual macromolecules. The essential feature of the polymers in question consisted in the strong sensitivity of the shape of the particles to the polymer concentration and to the molar ratio of EO to NIPA monomer units. At low polymer concentration, the shape of the aggregates was mainly spherical, as indicated by the low Rg/Rh values (Fig. 12). The Rg/Rh ratio is informative of the shape of particles in solution. Anisotropic particles, such as rods and coils, possess high values of the ratio, while for particles of spheroid form, low values of the ratio are observed (for spher-... 

Another intriguing feature emerged when we examined PFS-PDMS diblock copolymers having a longer soluble block as well as an increased block ratio (1 12 and 1 18). Samples of the two polymers were prepared by the same protocol, i.e., subjected to the same thermal history. Dilute solutions in decane were heated for 30 min at 61 °C, cooled to room temperature over two hours and allowed to age for 24 hours. We have already shown, in Fig. la, that under these conditions, PFS50-PDMS300 formed dense rod-like structures in hexane. However, as... 

Fig. 2a-d. Stress-strain response of four PS/PB diblock copolymers with rod morphology with a nominal weight fraction of PB rods of 0.23 but increasing molecular weight of block components, at two different strain rates (a) SB2, (b) SB5, (c) SB8, (d) SBIO. ( ) 1.3xl0 s- (O) 1.3x... 

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