Energy Transfer Studies of the Boundary Layer Interphase in Polystyrene-Poly(methyl methacrylate) Block Copolymer Films

Ni, Shaoru; Zhang, Ping; Wang, Yongcai; Winnik, Mitchell A.

doi:10.1021/ma00098a031

Cited by 69 publications

(123 citation statements)

References 11 publications

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“…We used the same spectroscopic procedure for determination of R 0 as that described previously. 18 The main characteristics of the block copolymers are listed in Table 1. Volume fractions were calculated by assuming that the densities of the PI and the PMMA blocks are the same as those for the pure homopolymer (F PI ) 0.913 g/cm 3 and F PMMA ) 1.188 g/cm 3 ).…”

Section: Methodsmentioning

confidence: 99%

“…This type of behavior has been noted previously. 9, 18,19,25 Here, the A 1 term represents the contribution of DET to the donor decay, and the A 2 term represents the independent fluorescence of the donor not involved in energy transfer. The exact physical meaning of the A 2 term is not yet known.…”

Section: Data and Data Analysismentioning

confidence: 99%

“…3c From the point of view of block copolymer morphology, the parameter of greatest interest is λ, related to R/δ, where R is the half-length of minor phase (see Figure 1). 18,19 This relationship depends on the geometry of the minor phase with following definitions for λ where R ) 1, 2, and 3 for lamellar, cylindrical, and spherical microdomains, respectively. Thus, the product λΦ in eq 5 gives us the volume of interphase.…”

Section: Data and Data Analysismentioning

confidence: 99%

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Energy Transfer in Restricted Geometry: Polyisoprene−Poly(methyl methacrylate) Block Copolymer Interfaces

Tcherkasskaya

Spiro

et al. 1996

J. Phys. Chem.

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The kinetics of direct nonradiative energy transfer between dyes confined to the 2.6 nm wide interface region of polyisoprene-poly(methyl methacrylate) block copolymer films are reported. This system differs from restricted geometry systems examined previously because of the diffuse nature of the edges of the confining space. The interface thickness is similar in magnitude to the characteristic distance for energy transfer (R 0 ) 2.3 nm) for the donor-acceptor dye pair (phenanthrene-anthracene) employed here. Samples were prepared from matched pairs of block copolymers, one containing a donor dye and the other an acceptor dye, at the PI-PMMA junction. Donor fluorescence decay profiles were fitted to the Klafter-Blumen expression [I D (t) ) A 1 exp{-(t/τ D ) -P(t/τ D ) } + A 2 exp(-t/τ D )] containing the additional A 2 term to account for donors (ca. 3%) outside the interface. The parameters obtained followed the predicted behavior, namely, that the preexponential term P was proportional to the acceptor concentration, whereas the stretched-exponential parameter was independent of the global acceptor concentration C A for acceptor-to-donor ratios C A /C D > 1. One of the most unusual features of the data is a crossover in observed as a function of a global acceptor concentration C A for a certain range of donor-acceptor composition, C A /C D < 1.

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Section: Methodsmentioning

confidence: 99%

Section: Data and Data Analysismentioning

confidence: 99%

Section: Data and Data Analysismentioning

confidence: 99%

See 1 more Smart Citation

Energy Transfer in Restricted Geometry: Polyisoprene−Poly(methyl methacrylate) Block Copolymer Interfaces

Tcherkasskaya

Spiro

et al. 1996

J. Phys. Chem.

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“…[19,20] The critical micelle concentration (CMC) was determined to be 9 Á 10 --7 mol Á L À1 (5 Á 10 À2 g Á L À1 ).…”

Section: Experimental Partmentioning

confidence: 99%

Nanoparticles by ROMP in Nonaqueous Emulsions

Haschick¹,

Klapper²,

Wagener³

et al. 2010

Macro Chemistry & Physics

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The use of nonaqueous emulsions to synthesize particles by ROMP is described. The applied emulsions – consisting of two immiscible, organic, aprotic solvents – are versatile reaction systems for the preparation of polymer particles from moisture sensitive monomers and catalysts. Whereas up to now only polycondensations or polyadditions have been utilized in nonaqueous emulsions, catalytic polymerizations are now presented. Four different functionalized norbornene derivatives were applied for ROMP by a second‐generation Grubbs catalyst to form polymer nanoparticles. Furthermore, core/shell and surface functionalized nanoparticles applicable to “click” reactions were prepared to demonstrate the use of different polymerization procedures in one pot.magnified image

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“…A single exponential decay was observed for phenanthrene polymer in the absence of any acceptor. 101 When the anthracene labeled was introduced, a rapid decay component was observed as a result of energy transfer. For a random distribution of donors and acceptors, the donor fl uorescence intensity decay I D ( t ) can be described by a modifi ed F ö rster equation (Eq.…”

Section: Rates Of Electron or Exciton Migrationmentioning

confidence: 99%