Polystyrene poly diblock

In order to improve the tribological properties of molecular films, molecular surface modification is the first choice to make an approach. A Diblock polymer polystyrene-poly(ethylene)oxide (PS-PEO) thin-films were studied in our previous research because of its interesting structure (one... 

Much work on the preparation of nonaqueous polymer dispersions has involved the radical polymerization of acrylic monomers in the presence of copolymers having the A block the same as the acrylic polymer in the particle core 2). The preparation of polymer dispersions other than polystyrene in the presence of a PS-PDMS diblock copolymer is of interest because effective anchoring of the copolymer may be influenced by the degree of compatibility between the PS anchor block and the polymer molecules in the particle core. The present paper describes the interpretation of experimental studies performed with the aim of determining the mode of anchoring of PS blocks to polystyrene, poly(methyl methacrylate), and poly(vinyl acetate) (PVA) particles. 

Figure 7.13 (A) Hydraamphiphile and (B) polystyrene-poly(propy ene imine) diblock structures...

Chuai C et al. (2004) Influence of diblock copolymer on the morphology and properties of polystyrene/poly(dimethylsiloxane) blends. J Appl Poly Sci 92(5) 2747-2757... 

Few examples of the homogeneous diblock-incompatible homo-polymer behavior have been reported. One that has received considerable attention is the system polystyrene-poly-a-methylstyrene (2). Block copolymers of styrene and a-methylstyrene exhibit a single loss peak in dynamic experiments (2,3) and have been shown to be thermorheologi-cally simple (4) hence they are considered to be homogeneous. Mechanical properties data on these copolymers also has been used to validate interesting extensions of the molecular theories of polymer viscoelasticity (2,3,4). 

Figure 3. Size exclusion chromatograms of (A) polystyrene front block (Mn 40,000 g/mole) and (B) polystyrene/poly(isobutyl methacrylate) diblock copolymer (Mn 50,000 g/mole).

Fig. 48a. Normalized inverse scattering intensity NS l(q, e) observed in the Monte Carlo simulation of a block copolymer model on the simple cubic lattice (see Fig. 44) plotted vs the normalized inverse temperature eN. b Reciprocal structure factor S (q ) -l(cxrcfes, left scale) and q ( squares, right scale) plotted vs temperature for a nearly symmetric diblock copolymer of polystyrene/poly (cis— 1,4) isoprene (Mw = 15 700). Filled symbols refer to cooling, open symbols to heating runs. The straight tine indicates the extrapolation to a spinodal temperature (T,) that occurs above the actual transition temperature (Tmst). where the data show a jump. From Stuhn et al. [323],...

SUN Sun, S.F., Light scattering studies of deuterated polystyrene-poly(methyl methacrylate) diblock copolymers in 1,4-dioxane solutions, Makromol. Chem., Rapid Commun., 4,203,1983. 

More recently, in a series of papers [84-86], Brown has analyzed the improvement in adhesion between two immiscible polymers [i.e., poly(methyl methacrylate) (PMMA) and polyphenylene oxide (PPO)] by the presence of polystyrene-PMMA diblock copolymers. Since one of the blocks is PMMA and the other is polystyrene (PS), which is totally miscible with PPO, it was reasonably expected that the copolymer organizes at the... 

More recently, Dai and coworkers successfully prepared ordered mesoporous carbon films with open-framework structures by using resorcinol and formaldehyde as carbon sources and diblock copolymer polystyrene-poly(4-vinylpyridine) (PS-P4VP) as a template [72]. Similar results were reported by Tanaka et al. [73], in which the same carbon precursor and triblock copolymer F127 (EO106PO70EO106) were used for organic-organic self-assembly. Triethyl... 

Rieger and coworkers [332] reported a surfactant free RAFT emulsion polymerization of butyl acrylate and styrene using poly(A,iV-dimethylacrylamide) trithiocarbonate macromolecular transfer agent. They observed that the polymerizations were fast and controlled with molar masses that matched well the theoretical values and low polydispersity indexes. Monomer conversions close to 100% were reached and the polymerizations behaved as controlled systems, even at 40% solids contents. The products were poly(lV,lV-dimethyl acrylamide)-b-poly(/i-butyl acrylate) and poly(Al,Al-dimethylacrylamide)-b-polystyrene amphiphilic diblock copolymers formed in situ. 

Strobl GR, Bendler JT, Kambour RP, Shultz AR (1986) Thermally reversible phase separation in polystyrene/poly(styrene-co-4-bromostyrene) blends. Macromolecules 19 2683-2689 Tyler CA, Morse DC (2005) Orthorhombic Fddd network in triblock and diblock copolymer melts. Phys Rev Lett 94 208302... 

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 1991, we reported on the alignment of a lamellar microstructure in a block copolymer melt [63]. The material of this study was a symmetric polystyrene-poly(methyl methacrylate) diblock copolymer (PS-PMMA) of molecular weight 37,000. This copolymer was chosen because of the relatively strong dielectric contrast between the two blocks (cp = 2.55, = 3.78) and the relatively small... 

In order to give some perspective, let us consider one of the block copolymers studied by us, namely polystyrene-poly(methyl methacrylate) symmetric diblock of molecular weight 37,000 at 200°C. Using appropriate numbers for this material, and our theoretical prediction for the lamellar moduli B and K [54], the critical field is estimated to be 260 kV/cm for a l-/i,m gap and 8.2 kV/cm for a 1-mm gap. The incipient ripple wavelengths would be 0.14 and 4.3 /xm, respectively. The 18 kV/cm field used in several of our experiments can induce a ripple instability only if the gap size exceeds —200 /xm. 

Together with TEM, SEM investigations have been useful in the description of diblock copolymer polystyrene-/ -poly(acrylic acid) (PS-fc-PAA) particle formation (Figure 8.7), namely from vesicles and lamellae to unclosed and closed porous particles and on until final porous particles. Thus, Yu et al. have highlighted that these self-assembled microspheres have monodispersed nanopores that contribute to their high sorption capacity and sustained release behavior (Yu et al. 2014). 

One may wonder whether adsorption from selective solvents leads to more dense brushes. As was pointed out above, this implies that the anchoring blocks attract each other so that they are prone to form self-assembled structures. One therefore has to bear in mind that not only does adsorption take place from a micellar solution, but also that there is a good chance that these micelles, once they are on the surface, remain micelles so that inhomogeneous adsorption layers are produced. Examples of adsorption studies of diblock copolymers from selective solvents are those by Marra and Hair [46] (polystyrene-poly(ethylene oxide) from heptane/toluene on mica). 

Comprehensive two-dimensional liquid chromatography has seen a strong increase in popularity and in the number of applications in recent years. LC x SEC has been applied to a large number of problems in polymer science. For example, the technique has been used to provide a detailed analysis of polystyrene-poly(methyl methacrylate) diblock copolymers [29], to analyze well-defined star polylactides [30], and to study to the grafting reaction of methyl methacrylate onto EPDM [31] or onto polybutadiene [32]. 

Figure 7.16 Experimental phase diagram of a lamellar (LAM) hexagonally ordered cylinders diblock copolymer melt polystyrene-poly- (HEX) bodycentered cubic (BCC) modulated...

Zhang, L.F. and Eisenberg, A. (1996) Multiple morphologies and characteristics of Crew-Cut micelle-like aggregates of polystyrene- -poly(acrylic acid) diblock copolymers in aqueous solutions. Journal of the American Chemical... 

Al-Hussein M, Lohmeijer BGG, Schubert US, de Jeu WH (2003) Melt morphology of polystyrene-poly(ethylene oxide) metallo-supramolecular diblock copolymer. Macromolecules 36 9281-9284... 

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