Polystyrene-polyisoprene diblock

Figure 13.15 Reduced storage modulus versus reduced frequency arco for a lamellae-forming polystyrene-polyisoprene diblock copolymer (M = 22,000) at temperatures above the order-disorder transition temperature Todt = 152°C, and quenched to temperatures below it. The disordered samples show terminal behavior, and the ordered (but unoriented) ones show nonterminal behavior. (Reprinted with permission from Patel et al.. Macromolecules 28 4313. Copyright 1995, American Chemical...

Figure 13.22 Damping functions hf y) and hs y) for the fast and slow relaxation processes of a 15 wt% solution of a micelle-forming polystyrene-polyisoprene diblock copolymer (molecular weights, respectively, of 14,000 and 29,000) in a low-molecular-weight (A/ = 4,000) polyisoprene. Damping functions for linear and star polymers and for silica dispersion are shown for comparison. (From Watanabe et al. 1997, with permission from Macromolecules 30 5905. Copyright 1997, American Chemical Society.)...

Kesselman, E., Talmon, Y., Bang, J. et al. (2005) Cryogenic transmission electron microscopy imaging of vesicles formed by a polystyrene-polyisoprene diblock copolymer. Macromolecules, 38 (16), 6779-6781. 

Hasegawa, H., Tanaka, H., Yamasaki, K., andHashimoto, T. (1987) Bicontinuous microdomain morphology of block copolymers. 1. Tetrapod-network strucmre of polystyrene-polyisoprene diblock polymers. Macromolecules, 20,1651-1662. 

Fig. 8. Effect of varying composition on the ordered-phase symmetry in polystyrene-polyisoprene (PS-PI) diblock copolymers [92]...

The substantial work on polystyrene/polybutadiene and polystyrene/ polyisoprene blends and diblock and triblock copolymer systems has lead to a general understanding of the nature of phase separation in regular block copolymer systems (5,6). The additional complexities of multiblocks with variable block length as well as possible hard- and/or soft-phase crystallinity makes the morphological characterization of polyurethane systems a challenge. 

Figure 7. A split-screen image, with a TEM micrograph of a cubic structure in a polystyrene / polyisoprene star diblock copolynaer on the left half, and a computer simulation using the structure indicate in Figure 1 on the right half. The lattice parameter is approximately 300A, the dark regions correspond to polyisoprene and the light regions to polystyrene.

Figure 4.25. High magnification image.s obtained by transmission electron microscopy of stained thin sections of a hyperbolic mesopha.se of a linear diblock copolymer, polystyrene-polyisoprene, whose morphology follows the D-surface (single node circled in middle picture) and possibly the gyroid. Staining produces high contrast between the two block domains. Note the very different magnifications.

Fig. 12.12 Some examples of diblock copolymer morphologies. Transmission electron micrographs of stained samples of (a) the lamellar phase of a polystyrene-polyisoprene (PS-PI) diblock with PS fraction 0.64 (b) the hexagonal phase of a PS-poly(2-vinylpyridene) diblock with fps = 0.35 and (c) and (d) the gyroid phase of a PS-PI diblock with fps = 0.39, showing projections with approximate threefoid and fourfoid symmetries, respectiveiy. Aii sampies were rapidiy cooied from the meit and thus exhibit the meit-state morphoiogy. (Reprinted with permission from the American Chemicai Society.)...

Polymer (B) polystyrene-b-polyisoprene diblock copolymer 1997ZHA... 

Other examples of such detailed analysis of the structure with the aid of contrast variation can be found for partially deuterated polystyrene-polyisoprene (PS-Pl) diblock copolymer micelles in decane [86, 95] Pluronic (PEO-PPO-PEO) micelles in water [96, 97] PB-PEO micelles in water [85] or PEP-PEO micelles in water [44] or in water/ DMF mixture [98]. 

Steinhoff, B. Rullmann, M. Wenzel, M. Junker, M. Alig, I. Oser, R. Stuhn, B. Meier, G. Diat, O. Bosecke, P. Stanley, H. B. (1998) Pressure Dependence of the Order-to-Disorder Transition in Polystyrene/Polyisoprene and Polystyrene/Poly(methylphenylsiloxane) Diblock Copolymers, Macromoleculesy 31, 36-40. 

In addition, polymer micelles have been demonstrated to be more stable and also have a significantly lower cmc than surfactant micelles. Further discussion of surfactant micelles is beyond the scope of this review, and, instead, the reader is directed to a recent review article by Armes. In fact, the polymer building blocks need not be amphiphilic and such phase-separated nanostructures can be formed from completely hydrophobic or lipophilic diblock copolymers that contain two segments with differing solubility (such as polystyrene- -polyisoprene) and hence can undergo phase separation in selective solvents. One example of such completely hydrophobic phase-separated micelles are those reported by Wooley and coworkers, which can be obtained from toluene and acetone solutions of a [polystyrene-a/f-poly(maleic anhydride)]-fc-polyisoprene Iriblock. Conversely, inverse structures are also accessible and are known as reverse micelles. These can be formed by adding a nonsolvent for the hydrophilic block to afford the opposite of a conventional micelle, for which the hydrophilic core is surrounded by a hydrophobic shell in a hydrophobic surrounding media. There have been a handful of reports on the application of these reverse micelles, for example, as nanoreactors and for the extraction of water-soluble molecules. ... 

Fig. 15. Pulsed ELDOR (DEER) distance measurements on the ionic spin-probe TEMPO-4-carboxylate attached to ionic clusters in ionically modified diblock copolymers, (a) Schematic structure of a monoionic polystyiene-polyisoprene diblock copolymer modified by sulfonate end groups on the polyisoprene bloek (sample series S). (b) Schematic structure of an a,0)-zwitterionic polystyrene- ly-isoprene diblock copolymer modified by a quaternary ammonium end group on the polystyrene block and a sulfonate end group on the polyisoprene block (sample series Z). (c) Schematic structures of the polymer chains. Tlie solid line corresponds to the harder block polystyrene, the dotted line to the softer block polyisoprene. (d) Dependence of ionic cluster size (ri) and intercluster distance (r2> on molecular weight. Squares correspond to sample series Z, circles to sample series S, and diamonds to monionic homopolymers (polystyrene modified with quaternary ammonium end groups). The dotted and dashed lines are fits of a constant function. The solid line is the best-fit scaling law r2 = 2.09...

Lee W, Cho D, Chang T, Hanley KJ, Lodge TP. Characterization of polystyrene-b-polyisoprene diblock copolymers by liquid chromatography at the chromatographic critical condition. Macromol 2001 34 2353. 

Mass V, Bellas V, Pasch H. Two-dimensional chromatography of complex polymers, 7. Detailed study of polystyrene—block-polyisoprene diblock copolymers prepared by sequential anionic polymerization and coupling chemistry. Macromol Chem Phys 2008 209 2026-39. 

Sakurai S, Me H, Umeda H, Nomura S, Lee HH, Kim JK. Gyroid structures and morphological control in binary blends of polystyrene-block-polyisoprene diblock copolymers. Macromolecules 1998 31 336-43. 

Polystyrene-block-Polyisoprene (SI Diblock) Copolymer or Polyisoprene-block-Polystyrene (IS Diblock) Copolymer... 

Polystyrene-b-polyisoprene diblock copolymer (hydrogenated PIP) N,N-dimethylformamide and methylcyclohexane 93P01... 

Polystyrene-b-polyisoprene diblock copol)mier cyclohexane Enthalpy 335... 

LeiblerL., Theory of microphase separation in block copolymers. Macromolecules, 13, 1602, 1980. Eoerster S., Khandpur A.K., Zhao J., Bates E.S., Hamley I.W., Ryan A.J., and Bras W. Complex phase behavior of polyisoprene-polystyrene diblock copolymers near the order-disorder transition. Macromolecules, 21, 6922, 1994. 

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