Starlike Polymeric Architectures by Atom Transfer Radical Polymerization:  Templates for the Production of Low Dielectric Constant Thin Films

Heise, Andreas; Nguyen, Cattien V.; Malek, Raouf; Hedrick, James L.; Frank, Curtis W.; Miller, Robert D.

doi:10.1021/ma991091r

Cited by 113 publications

(142 citation statements)

References 49 publications

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“…The theoretical molecular weights (M theor ), calculated by conversion, were much higher than the M n values obtained by SEC. Such systematic error was reported in previous research work [28,30] and attributed to the difference in shape between the star polymers and the linear standards used in the SEC measurements. The monomodal curves and the absence of any shoulders clearly indicated that the initiating abilities of all the 2-bromo-2-methylpropionic…”

Section: Polymerization Of Styrenesupporting

confidence: 51%

Amphiphilic Multicore‐Shell Particles Based on Polyphenylene Dendrimers

Yin

Bauer

Klapper

et al. 2007

Macro Chemistry & Physics

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Six‐arm and twelve‐arm star polymers have been synthesized by ATRP on the template of first‐ and second‐generation polyphenylene dendrimers. Star polymers with amphiphilic double‐shell of hydrophilic HEMA and styrene were also synthesized and their behavior toward different solvents was studied. The results show that the size, conformation, and surface polarity of the amphiphilic double‐shell species can be adjusted by using solvents with varying polarity. In polar media, the hydrophilic blocks turn outwards, whereas in non‐polar media, the hydrophobic segments move to the molecules' surface; the macromolecule can rearrange its structure depending on the polarity of the surrounding media.magnified image

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Section: Polymerization Of Styrenesupporting

confidence: 51%

Amphiphilic Multicore‐Shell Particles Based on Polyphenylene Dendrimers

Yin

Bauer

Klapper

et al. 2007

Macro Chemistry & Physics

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“…ATRP was chosen as the polymerization technique for two reasons. First, by choosing the right reaction conditions, star-shaped polymers can be prepared in a controlled way with a minimal extent of star-star coupling [6][7][8][9][10][11][12][13][14][15] . Secondly, after ATRP of acrylates, a secondary bromine end group is available at the end of each arm of the stars for further conversion into reactive groups.…”

Section: Star-shaped Piba By Atrpmentioning

confidence: 99%

“…Recent developments in atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain-transfer polymerization (RAFT) made it possible to use radical polymerization for the controlled synthesis of star polymers [3][4][5] . For these techniques, a variety of multifunctional initiators has been developed and successfully used [6][7][8][9][10][11][12][13][14][15] .…”

Section: Introductionmentioning

confidence: 99%

Design and Use of Organic Nanoparticles Prepared from Star-Shaped Polymers with Reactive End Groups

et al. 2008

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Star-shaped poly(isobornyl acrylate) (PiBA) was prepared by atom transfer radical polymerization (ATRP) using multifunctional initiators. The optimal ATRP-conditions were determined to minimize star-star coupling and to preserve high end group functionality (>90%).Star-shaped PiBA with narrow polydispersity index was synthesized with 4, 6 and 12 arms and of varying molecular weight (10000 to 100000 g·mol -1 ) using 4 equivalents of a Cu(I)Br/PMDETA catalyst system in acetone. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) analysis, NMR spectroscopy and size exclusion chromatography (SEC) confirmed their controlled synthesis. The bromine-end group of each arm was then transformed to a reactive end group by a nucleophilic substitution with methacrylic acid or cinnamic acid (conversion >90%).These reactive star polymers were used to prepare PiBA-nanoparticles by intramolecular polymerization of the end groups. The successful preparation of this new type of organic nanoparticles on a multi-gram scale was proven by NMR spectroscopy and SEC. Subsequently, they have been used as additives for linear, rubbery poly(n-butyl acrylate). Rheology measurements indicated that the viscoelastic properties of the resulting materials can be finetuned by changing the amount of incorporated nanoparticles (1-20 wt%), as a result of the entanglements between the nanoparticles and the linear polymers.

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“…Multi-armed star-like polymers are three-dimensional macromolecules, in which a large number of linear arms of similar molecular weight emanate from a central core. Although many star-like polymers have been widely studied, 18 there is no report on star-like polymers used for gas separation. The three-dimensional microphase-separated structure in star-like polymers may be quite different from that of linear segmented ones, and the intermolecular packing of star-like polymers may also be different from the intersegmental packing of linear polymer chains.…”

mentioning

confidence: 99%

Synthesis and Gas Permeation Properties of Star-like Poly(ethylene oxide)s Using Hyperbranched Polyimide as Central Core

Yin

Yang

Yoshino

et al. 2004

Polym J

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ABSTRACT:A series of star-like poly(ethylene oxide)s were synthesized using anhydride-terminated hyperbranched polyimides as the central cores and poly(ethylene oxide)s (PEOs) as the linear arms. Their physical and gas permeation properties were investigated in comparison with those of PEO segmented block copolyimides (PEOPIs). The solubility of star-like PEOs was affected by the terminal groups. The amine-terminated star-like PEOs displayed better solubility property than the methoxy-and acetamido-terminated ones. The DSC and dynamic mechanical spectroscopy suggested the morphology of star-like PEOs was different from that of PEO-PIs. The thermo-mechanical property of amine-terminated star-like PEOs was significantly improved by cross-linking with ethylene glycol diglycidyl ether. The star-like PEO membranes were much more permeable to CO 2 than to N 2 and even to H 2 . However, their CO 2 separation performance was slightly lower than that of PEO-PIs, probably due to the difference in the morphology. The AgBF 4 -doped star-like PEO membrane with a loading of 40 wt% (corresponding to 67 wt% in PEO matrix) showed a very high ideal selectivity of C 2 H 4 /C 2 H 6 of more than 100 with a low ethylene permeability of 1:5 Â 10 À10 cm 3 (STP) cm À1 s À1 cm Hg À1 in single-component permeation at 2 atm and 308 K. However, the permselectivity decreased down to 14 in mixed gas permeation. The permeation behavior was discussed based on the solubility and diffusivity.KEY WORDS Star-like Polymer / Polyethylene Oxide / Membrane Separation / Polymer Electrolyte Membrane / Carbon Dioxide Separation / Ethylene/Ethane Separation / Membrane-based gas separations have attracted much attention in the past decade because they offer significant advantages over traditional separation processes such as low energy consumption, low capital investment cost and simple operation. A large number of polymeric materials have been studied for this application. However, most of the materials developed so far are limited mainly to linear type polymers. For example, many studies have been devoted to the investigation of the relationship between chemical structure and gas permeation property of polyimides (PIs) in order to develop membranes with both high permeability and high selectivity.1-5 On the other hand, very few attempts have been made using nonlinear (multibranched or multiarmed) polymers as membrane materials for gas separations. Hyperbranched PIs can be simply prepared by direct ''one-step'' polymerization of tri-functional amines with common acid dianhydrides.6 Hyperbranched PIs have rather poor membrane-forming ability, but their tough membranes can be fabricated by crosslinking treatment during membrane casting using the terminal functional groups.7 Their gas permeation properties significantly depend on both the terminal functional groups and the crosslinking. Poly(ethylene oxide) (PEO) and PEO-containing polymers have been extensively studied for gas separations. [8][9][10][11][12][13][14][15] Poly(ethylene-oxide imide) segmented b...

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Starlike Polymeric Architectures by Atom Transfer Radical Polymerization: Templates for the Production of Low Dielectric Constant Thin Films

Cited by 113 publications

References 49 publications

Amphiphilic Multicore‐Shell Particles Based on Polyphenylene Dendrimers

Amphiphilic Multicore‐Shell Particles Based on Polyphenylene Dendrimers

Design and Use of Organic Nanoparticles Prepared from Star-Shaped Polymers with Reactive End Groups

Synthesis and Gas Permeation Properties of Star-like Poly(ethylene oxide)s Using Hyperbranched Polyimide as Central Core

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