Transition from Mushroom to Brush during Formation of a Tethered Layer

Huang, Hui; Rankin, Stephen E.; Penn, Lynn S.; Quirk, Roderic P.; Cheong, Tae Hee

doi:10.1021/la030422x

Cited by 37 publications

(61 citation statements)

References 25 publications

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“…Penn and colleagues have reported the evolution of various regimes of kinetics during tethering of end‐functionalized PS from solution onto Si surfaces 63. They were able to image mushroom, brush, and intermediate shapes.…”

Section: Resultsmentioning

confidence: 99%

Silicon surface modification with trialkoxysilyl‐functionalized star‐shaped polymers

Viswanathan

Long

Ward

2005

J. Polym. Sci. A Polym. Chem.

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The synthesis of trimethoxysilane end-capped linear polystyrene (PS) and star-branched PS and subsequent silicon (Si) surface modification with linear and star polymers are described. Trimethoxysilane terminated PS was synthesized using sec-butyl lithium initiated anionic polymerization of styrene and subsequent end-capping of the living anions with p-chloromethylphenyl trimethoxysilane (CMPTMS). 1 H and 29 Si NMR spectroscopy confirmed the successful end-capping of polystyryllithium with the trimethoxysilane functional group. The effect of a molar excess of end-capper on the efficiency of functionalization was also investigated, and the required excess increased for higher molar mass oligomers. Acid catalyzed hydrolysis and condensation of the trimethoxysilane end-groups resulted in star-branched PS, and NMR spectroscopy and SEC analysis were used to characterize the star polymers. This is the first report of core-functionalized star-shaped polymers as surface modifiers and the first comparative study showing differences in surface topography between star and linear polymer modified surfaces. Surface-sensitive techniques such as ellipsometry, contact angle goniometry, and AFM were used to confirm the attachment of star PS, as well as to compare the characteristics of the star and linear PS modified Si surfaces. The polymer film properties were referenced to polymer dimensions in dilute solution, which revealed that linear PS chains were in the intermediate brush regime and the star-branched PS produced a surface with covalently attached chains in the mushroom regime. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: [3655][3656][3657][3658][3659][3660][3661][3662][3663][3664][3665][3666] 2005

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Section: Resultsmentioning

confidence: 99%

Silicon surface modification with trialkoxysilyl‐functionalized star‐shaped polymers

Viswanathan

Long

Ward

2005

J. Polym. Sci. A Polym. Chem.

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“…We recommend that S be determined to evaluate whether a ''grafting-to'' method produces a film in the brush regime. Penn and coworkers 39,40 have arguably performed some of the most systematic research on the ''grafting-to'' technique. They have reported results that suggest the ''grafting-to'' technique can produce sufficiently high grafting densities to qualify as conformationally stretched chains.…”

Section: The Definition Of a Polymer Brush By Characteristic Parametementioning

confidence: 99%

A structural definition of polymer brushes

Brittain

Minko

2007

J. Polym. Sci. A Polym. Chem.

552

652

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ABSTRACT:In this article, we consolidate several literature reports in an attempt to provide a structural definition of a polymer brush as a tethered polymer layer with a high grafting density of polymer chains. We will try to distinguish a brush from grafted polymer layers and coated layers and provide a reasonable approach to the description of the brush regime with a single parameter S-reduced grafting density. Furthermore, we will attempt to describe the relevance of this description to applications. This article is timely given the continuing interest relating to brushes on flat substrates, nanoparticles, and the walls of micro-channels.

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“…Lower brush densities are expected from the grafting to technique, as the hydrodynamic volume of the individual polymer chains excludes potential grafting sites in the initial stages of attachment. [24,25] Solvent-sensitive stimuliresponsive brush systems are often composed of either block copolymers [3,14,26] or mixed polymer brushes. [13,22,27] In either case, two distinct polymer constituents of dramatically different surface energy characteristics are present on the surface so that changes in wettability occur upon switching.…”

mentioning

confidence: 99%