Solvent-Induced Length Variation of Cylindrical Brushes

Fischer, Karl; Schmidt, Manfred

doi:10.1002/1521-3927(20010701)22:10<787::aid-marc787>3.0.co;2-y

Cited by 108 publications

(109 citation statements)

References 12 publications

(16 reference statements)

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“…The latter value indicates that one brush molecule occupies on average 490 000 nm 3 , i.e. (79 nm) 3 . For the brushes B2 and B3 this volume is approximately (75 nm) 3 and (76 nm) 3 .…”

Section: Brush Copolymer Solution Propertiesmentioning

confidence: 99%

“…(79 nm) 3 . For the brushes B2 and B3 this volume is approximately (75 nm) 3 and (76 nm) 3 . The distance between the mass centers of the brushes is below 80 nm and is comparable to the length of an extended brush (%60 nm) and the apparent hydrodynamic diameter values determined by DLS.…”

Section: Brush Copolymer Solution Propertiesmentioning

confidence: 99%

“…Conformational behavior of molecular brushes in solution and at interfaces has been studied theoretically and experimentally. Polymer conformation can be influenced by external factors, such as solvent, [3] light, [4] and temperature. [5] Conformational changes of single molecules were observed, and the mechanism and driving forces for the conformational variation can be unique for a specific brush molecule.…”

Section: Introductionmentioning

confidence: 99%

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Solution Behavior of Temperature‐Responsive Molecular Brushes Prepared by ATRP

Pietrasik

Sumerlin

Lee

et al. 2007

Macro Chemistry & Physics

106

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Molecular brushes, with side chains consisting of two copolymers: 2‐(dimethylamino)ethyl methacrylate with methyl methacrylate, and N,N‐dimethylacrylamide with butyl acrylate were prepared by grafting‐from via atom transfer radical polymerization (ATRP). Poly(2‐(2‐bromoisobutyryloxy)ethyl methacrylate) and poly(2‐(2‐bromopropionyloxy)ethyl methacrylate) were used as macroinitiators. Dynamic light scattering (DLS) studies were performed for aqueous solutions of molecular brushes below and above the lower critical solution temperature (LCST), and an unusual concentration‐dependent LCST was observed. Due to the compact structure of molecular brushes, intramolecular collapse can occur when the average distance between molecules is much larger than the hydrodynamic dimensions of the individual macromolecules. However, if the concentration of the solution of molecular brushes is increased to the level in which the separation distance is comparable with the brush hydrodynamic dimensions, intermolecular aggregation occurs, as typically observed for solutions of linear polymers.magnified image

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“…The latter value indicates that one brush molecule occupies on average 490 000 nm 3 , i.e. (79 nm) 3 . For the brushes B2 and B3 this volume is approximately (75 nm) 3 and (76 nm) 3 .…”

Section: Brush Copolymer Solution Propertiesmentioning

confidence: 99%

Section: Brush Copolymer Solution Propertiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Solution Behavior of Temperature‐Responsive Molecular Brushes Prepared by ATRP

Pietrasik

Sumerlin

Lee

et al. 2007

Macro Chemistry & Physics

106

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“…These results are similar to those observed for PS-MA PM in toluene and cyclohexane. 17,19 The unperturbed mean-square radius of gyration, /S 2 S 0 , for wormlike chains with a contour length L is expressed as 20…”

Section: Resultsmentioning

confidence: 58%

“…This differs from the known behavior of linear PS and benzyl-PS PM in the same solvent in that A 2 decreases with decreasing T and becomes zero at 34.5 1C, [13][14][15][16] but the results are similar to those observed for PS-MA PM. 17,19 The molecular weight dependence of A 2 for butyl-PS PM is illustrated in Figure 4, in which the filled and unfilled circles represent the data points for the toluene and cyclohexane solutions, respectively. The data points for the cyclohexane solutions are systematically lower than those for the toluene solutions, showing that the former solvent is poorer than the latter solvent.…”

Section: Scattering Functionmentioning

confidence: 95%

Effects of side-chain ends on the stiffness and excluded-volume parameters of polymacromonomers

Kanda

Nakamura

2011

Polym J

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Light and small-angle X-ray scattering measurements were taken on cyclohexane and toluene solutions of a polystyrene (PS) polymacromonomer (PM) having side chains consisting of 19 styrene residues and an n-butyl group (butyl-PS PM) at each end. The second virial coefficient, A 2 , of the butyl-PS PM in cyclohexane was positive in the temperature range of 15.0-34.5 1C, differing from previous results for PS PMs with benzyl ends (benzyl-PS PM) whose A 2 vanished at 34.5 1C. The mean-square radius of gyration, /S 2 S, for the butyl-PS PM in cyclohexane at 34.5 1C was much larger than that for the benzyl-PS PM with the same side-chain length, indicating large effects of the side-chain ends on intramolecular interactions, whereas the difference in /S 2 S between these polymers in toluene at 15.0 1C was quite small. From these data, the stiffness parameter and the excluded-volume strength were determined with the aid of theories for the wormlike chain model. The effects of the side-chain ends on these parameters are discussed according to recently developed theories. Polymer Journal (2012) 44, 252-256; doi:10.1038/pj.2011.132; published online 14 December 2011Keywords: branched polymer; light scattering; polymacromonomer; polystyrene; small-angle X-ray scattering; solution properties INTRODUCTIONThe second virial coefficient, A 2 , of linear polystyrene (PS) with a butyl end in cyclohexane at the Y temperature (34.5 1C) was known to increase with decreasing molecular weight, M, when M is lower than 10 4 , which had been considered to be the effects of the threesegment interactions. 1 Yamakawa 2 interpreted this increase as an effect of chain ends in 1992. Since then, studies were undertaken to address the chain-end effect on A 2 for several kinds of polymers. 3-9 Among them, PS solutions were the most precisely examined. Because the chain-end effect on A 2 of linear PS with a benzyl end, in contrast to a butyl end, was negligibly small, 7 the increase in A 2 of PS at low M was ascribed to the effects of the butyl end. Recently, a similar study was carried out on the A 2 of a four-arm star PS with a butyl group at each arm end and showed that the increase in A 2 at Y with decreasing M begins at a higher value of M than that for linear PS with the same end group. 8 This study indicates that the chain-end effect becomes more significant with an increasing number of branches. Therefore, one may expect the chain-end effect to be much larger for comb polymers that have many more branches.Polymacromonomer (PM), a type of comb-branched polymer with dense side chains, is known to behave as a stiff chain in solution because of the interactions between its side chains. [10][11][12] We have studied PM consisting of a PS main chain and PS side chains with a benzyl group at each end (benzyl-PS PM) and showed that its A 2 in cyclohexane vanishes at 34.5 1C, which is identical to the Y temperature of linear PS in cyclohexane. [13][14][15][16] In contrast, the values of A 2 for PM consisting of a polymethacrylate main chain and PS sid...

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Dendronized Polymers

Schlüter¹,

Rabe²

2001

Encyclopedia of Polymer Science and Technology

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Synthesis, properties, and application of the novel class of comb polymers with dendritic side chains (dendronized polymers) are discussed. Different synthetic strategies are discussed and compared. The assembly and manipulation of homo‐ and amphiphilic representatives are treated with an emphasis on interfacial issues. The combination of neutron scattering data in solution, molecular dynamics simulations in vacuum, and scanning force microscopical investigations of ultrathin layers as well as individualized representatives of dendronized polymers adsorbed on highly oriented pyrolytic graphite show that dendronized polymers can be considered rigid, nano‐sized molecular objects with cylindrical shapes, depending on structure, size, and density of attachment. Although experiments were only recently started accordingly, it has already become obvious that this class of polymers, because of their size and shape and potential to be equipped with various surface functionalities and patterns, links the worlds of materials science and bioscience.

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Solvent-Induced Length Variation of Cylindrical Brushes

Cited by 108 publications

References 12 publications

Solution Behavior of Temperature‐Responsive Molecular Brushes Prepared by ATRP

Solution Behavior of Temperature‐Responsive Molecular Brushes Prepared by ATRP

Effects of side-chain ends on the stiffness and excluded-volume parameters of polymacromonomers

Dendronized Polymers

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