Copolymers of poly styrene-b-

Dispersions of poly(vinyl acetate) in -alkanes have been prepared using a diblock copolymer of poly(styrene-b-[ethylene-co-propylene]) as the stabilizer for the colloidal PVAc. The dispersing agent contained 38.5% styrene and was used at a concentration of 1-5 wt%. The monomer concentration ranged from 10 to 30 wt% in the various experiments. A typical initiator was 2,2 -azobisisobu-tyronitrile. The particle diameters were in the range of 0.10 to 0.31 fan [179],... 

Several other examples have been reported in the literature in which one single BCP has been used. On the contrary, studies using blends are rather scarce. Krausch and coworkers [57] adsorbed a linear ABC triblock copolymer of poly(styrene-b-2-vinylpyridine-b-tert-butylmethacrylate) onto the SiO surface of a silicon wafer to fabricate a nanostructured support and analyze the microphase separation of a polymer blend on this substrate. The BCP used exhibits a lateral microphase separation as a consequence of the strong affinity of the middle block [ie, poly(vinylpyrrolidone) (PVP)] to the boundary surface. Interestingly, the phase separation of the homopolymers... 

Among the few examples it is worth mentioning the work of Seo et al. [84] that studied the structures formed at the air/water interface of BCP/BCP blends using a symmetric monodisperse diblock copolymer of poly(styrene-b-ferrocenylsilane)... 

Another interesting design of mixed polymer brushes was obtained by sequential grafting of asymmetric nonsticky/sticky diblock copolymers of poly(styrene-b-3-(trimethoxysilyl)propylmethacrylate) and monomethoxypoly(ethylene glycol)-trimethoxysilane onto silicon wafers (Han et al., 2013). The nanoscopic morphology of these mixed polymer brushes exhibited stimuli responsive behavior to various temperatures and solvents. 

Pan et al. prepared a macroinitiator by chloromethylation of a commercially available AB block copolymer of poly (styrene-b-ethylene-co-propylene) (SEP) and used it as a macroinitiator for the ATRP of ethyl methacrylate (EMA) [302]. The kinetic plot showed Uttle evidence of termination during the reaction and the molecular weight of the graft copolymer increased linearly with the monomer conversion, resulting in a final M =73,200 and M Mj,=1.22. The weight ra-... 

Brown and White employed this approach to prepare block copolymers of styrene and mcthacrylic acid (6). They were able to hydrolyze poly(styrene-b-methyl methacrylate) (S-b-MM) with p-toluenesulfonic acid (TsOH). Allen, et al., have recently reported acidic hydrolysis of poly(styrene-b-t-butyl methacrylate) (S-b-tBM) (7-10). These same workers have also prepared potassium methacrylate blocks directly by treating blocks of alkyl methacrylates with potassium superoxide (7-10). 

R.F. Storey, B.J. Chisholm, and M.A. Masse, Morphology and physical properties of poly(styrene-b-isobutylene-b-styrene) block copolymers, Polymer, 37(14) 2925-2938, July 1996. 

Riess G, Rogez D (1982) Micellization of poly(styrene-b-ethylene oxide) block copolymers, ACS Polym Prepr (Div Polym Chem) 23 19-20... 

In similar approach it was possible to obtain cadmium sulfide nanocrystals in block copolymer micelles of poly(styrene-b-2-vinylpyridine) [240-242], Further approaches have been described recently by Antonietti [243],... 

Hydrolysis of Poly(styrene-b-tBuA) Diblock Copolymer... 

FIGURE 13.16 AFM phase images of poly(styrene-b-isobutylene-b-styrene) (SIBS) triblock copolymers. The images are for (a) polyisobutylene homopolymer (b) branched SIBS with 16% styrene content and (c) linear SIBS with 30% styrene. The darker regions have greater hardness and thus represent the polystyrene domains. (From Puskas et al. (2000) reprinted with permission from John Wiley Sons, Ltd., copyright 2003.)... 

The first proof of the validity of this approach was given by Gankina et al. [19] for the analysis of block copolymers by thin layer chromatography. Column liquid chromatography was used by Zimina et al. [20] for the analysis of poly(styrene-b/ock-methyl methacrylate) and poly(styrene-Wock-terr-butyl methacrylate). However, the critical conditions were established only for the polar part of the block copolymers, i.e. PMMA and PtBMA, respectively. Thus, only the polystyrene block was analyzed. 

A. R. A. Schettini, D. Khastgir, B. G. Soares, Microwave Dielectric Properties and EMI Shielding Effectiveness of Poly(Styrene-B-Styrene-Butadiene-Styrene) Copolymer Filled with PAni.Dodecylbenzenesulfonic Acid and Carbon Black. Polym. Eng. Sci. 2012, 52, 2041-2048. 

O Driscoll reports that several polymer-monomer combinations were used in the controlled preparation of homo- and block polymers by ultrasonic radiation(108). Similarly, Fujiwara reports the preparation of poly(styrene-b-methyl methacrylate) by ultrasonic degradation of polystyrene(109). The utility of ultrasonic irradiation is limited since yields are usually low, and the block copolymer is often contaminated with relatively large amounts of the homopolymers. 

Yang H., Sa U., Kang M., Ryu H.S., Ryu C.Y., Cho K., Near-surface morphology effect on tack behavior of poly(styrene-b-butadiene-b-styrene) triblock copolymer/rosin films. Polymer, 47(11), 2006, 3889-3895. 

Poly(dimethylsiloxane) (PDMS) is a well-known hydrophobic polymer with higher repellency for water than PS crosslinked siUcone elastomers (WCA = 112° for a smooth film) are commonly used for fabricating microfluidic devices. But forming solid fibers comprised solely of linear PDMS is not possible, due to its low glass transition temperature. Instead of using linear homopolymer PDMS, Ma et al. [21] electrospun fibers of poly(styrene-b-dimethylsiloxane) block copolymers blended with 23.4 wt% homopolymer polystyrene (PS-PDMS/PS) from a solution in a mixed solvent of THF and DMF. The resultant fiber mat, with fiber diameters in the range of 150-400 nm, exhibited a WCA of 163° and a hysteresis of 15°. An illustration of water droplets beaded up on such a mat is provided in Fig. 3. A PS mat of similar fiber diameter and porosity exhibited a WCA of only 138°. The difference was attributed to the lower surface tension of the PDMS component, combined with its spontaneous segregation to the fiber surface. X-ray photoelec-... 

Xu et al. (1999a) prepared compatibilized blends of PS and the Zn salt of sulfonated PS by addition of poly(styrene-b-4-vinylpyridine) diblock copolymer. Characterization methods included SEM, DSC, SAXS, and FTIR. The effect of block copolymer level was studied. Evidence was found for Zn-mediated cross-linking between sulfonate groups and pyridine nitrogen. 

Figure 10.3 TEM images of poly(styrene-b/oc

There is current interest in the use of block copolymers to help create structures that have potential sensor applications, e.g. block copolymers of poly styrene-poly (methyl methacrylate) (PS-b-PMMA). The nature of the organization that is created in thin films is influenced by the factors influencing phase separation of the polymers and very importantly the surface energy of the substrate on which they are deposited (Figure 8.14). If a substrate is patterned and then certain areas chemically modified, a substrate is created with variation in the surface energy across the surface. This is discussed in more detail in Chapter 9. The differences in surface energy will influence the morphology created. 

Ramakrishnan, A., and Dhamodharan, R. (2000). A novel and simple method of preparation of poly(styrene-b-2-vinylpyridine) block copolymer of narrow molecular weight distribution living anionic polymerization followed by mechanism transfer to controlled/iivingc radical polymerization (ATRP). J. Macromol. ScL, Pure Appl. Chem., A37(6) 621-631. 

Yoshida, E., and Sugita, A. (1998). Synthesis of poly(styrene-b-tetrahydrofuran-b-styrene) triblock copolymers by transformation from living cationic into living radical polymerization using 4-hydroxy-2,2,6,6-tetramethylpiperidine-l-oxyl as a transforming agent. J. Polym. Sci.,... 

Pan, Q., et al. (1999). Synthesis and characterization of block-graft copolymers composed of poly(styrene-b-ethylene-co-propylene) and poly(ethyl methacrylate) by atom transfer radical pol5merization. J. Polym. ScL, Part A Polym. Chem., 57(15) 2699-2702. 

Fig. 10.9 Reflectance (blue) and transmission (yellow) measurements of poly(styrene-b-isoprene) block copolymer with molecular weights as shown...

Second virial coefficient of poly(styrene-b-isoprene) (polyblock copolymer)... 

Huang CM, Wei KH, Jeng US, Liang KS. Structural evolution of poly(styrene-b-4-vinylpyridine) diblock copolymer/gold nanoparticle mixtures from solution to solid state. Macromolecules 2007 40 5067-74. 

Here we describe an example of the fabrication and investigation of smart responsive nanoparticles by grafting block-copolymers. We grafted triblock copolymer of poly(styrene-fc-2-vinylpyridine-fc-ethyleneoxide) (P(S-b-2VP-b-EO) to silica particles 200 nm in diameter (Fig. 18.9). The particles were modified by 11-bromoundodeciltrimethoxisilane (BUDTMS), then the block-copolymer was grafted by a quatemization reaction to the particle surface. The grafting of the block-copolymer to the silica nanoparticles was proved by FTIR using the diffuse reflection technique. Very well-pronounced... 

Waldman D A, Kolb B U, McCarthy T J and Hsu S L 1988 Infrared study of adsorbed monolayers of poly(styrene-propylene sulphide) (PS-PPS) block copolymers Polym. Mater. Sc/. Eng. 59 326-33... 

As previously described, all microspheres discussed in this chapter were synthesized from AB type diblock copolymers. Precursor block copolymers, poly(styrene-b-4-vinyl pyridine) (P[S-b-4VP]) diblock copolymers, were synthesized using the additional anionic polymerization technique [13]. The basic properties of the block copolymers were determined elsewhere [24,25] and are listed... 

Cao X. and Faust R., Polyisobutylene based thermoplastic elastomer 5. Poly(styrene-b-isobutylene-b-styrene) tri-block copolymers by coupling of living poly(styrene-b-isobutylene) di-block copolymers. Macromolecules, 32, 5487, 1999. 

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