The role of activator and deactivator species in the surface-initiated atom-transfer radical polymerization of styrene using CuBr/CuBr2/pentamethyldiethylenetriamine as a model system is described. The influence of initially added deactivator with respect to the degree of controlling the layer growth and thickness is studied. Variation of the activator concentration results in changes of the kinetics as well as brush thicknesses consistent with the well-known rate laws of ATRP.

R. Dhamodharan

Department Of Chemistry

Bromine

copolymer

Copper

DIETHYLENETRIAMINE

Styrene

article

chemical structure

film

Polymerization

reaction time

reproducibility

surface property

THAWING

Thickness

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Polymer Brushes via ATRP: Role of Activator and Deactivator in the Surface‐Initiated ATRP of Styrene on Planar Substrates

Macromolecular Rapid Communications

Controlled radical polymerization of cyclohexyl methacrylate (CHMA), at ambient temperature, using various chain transfer agents (CTAs) is successfully demonstrated via single electron transfer-radical addition fragmentation chain transfer (SET-RAFT). Well-controlled polymerization with narrow molecular weight distribution (Mw/Mn) &lt; 1.25 was achieved. The polymerization rate followed first-order kinetics with respect to monomer conversion, and the molecular weight of the polymer increased linearly up to high conversion. A novel, fluorescein-based initiator, a novel fluorescent CTA and two other CTAs comprising of butane thiol trithiocarbonate with cyano (CTA 1) and carboxylic acid (CTA 3) as the end group were synthesized and characterized. The polymerization is observed to be uncontrolled under SET and less controlled under atom transfer radical polymerization (ATRP) condition. CTA 2 and 3 produces better control in propagation compared with CTA 1, which may be attributed to the presence of R group that undergoes ready fragmentation to radicals, at ambient temperature. The poly(cyclohexyl methacrylate) [P(CHMA)] prepared through ATRP have higher fluorescence intensity compared with those from SET-RAFT, which may be attributed to the quenching of fluorescence by the trithiocarbonate and the long hydrocarbon chain. It is observed that block copolymers P(CHMA-b-t-BMA) produced from P(CHMA) macroinitiators synthesized via SET-RAFT result in lower polydispersity index in comparison with those synthesized via ATRP. © 2010 Wiley Periodicals, Inc.

Journal of Polymer Science, Part A: Polymer Chemistry

Controlled polymerization of methacrylates at ambient temperature using trithiocarbonate chain transfer agents via SET-RAFT-cyclohexyl methacrylate: A model study

The surface-initiated ATRP of benzyl methacrylate, methyl methacrylate, and styrene from magnetite nanoparticle is investigated, without the use of sacrificial (free) initiator in solution. It is observed that the grafting density obtained is related to the polymerization kinetics, being higher for faster polymerizing monomer. The grafting density was found to be nearly 2 chains/nm 2 for the rapidly polymerizing benzyl methacrylate. In contrast, for the less rapidly polymerizing styrene, the grafting density was found to be nearly 0.7 chain/nm 2. It is hypothesized that this could be due to the relative rates of surface-initiated polymerization versus conformational mobility of polymer chains anchored by one end to the surface. An amphiphilic diblock polymer based on 2-hydroxylethyl methacrylate is synthesized from the polystyrene monolayer. The homopolymer and block copolymer grafted MNs form stable dispersions in various solvents. In order to evaluate molecular weight of the polymer that was grafted on to the surface of the nanoparticles, it was degrafted suitably and subjected to gel permeation chromatography analysis. Thermogravimetric analysis, transmission electron microscopy, and Fourier transform infrared spectroscopy were used to confirm the grafting reaction. © to the authors 2009.

Fulltext

Nanoscale Research Letters

Synthesis of polymer grafted magnetite nanoparticle with the highest grafting density via controlled radical polymerization

In this work, we describe the use of hydridosilanes for the attachment of polymer monolayers to SiO2 surfaces. In one approach, first a benzophenone group containing hydridosilane is self-assembled on the SiO 2 surface followed by photochemical attachment of polymer chains deposited onto the monolayer. In a second approach an ATRP initiator is self-assembled to the substrate surface, again using hydridosilane anchor groups. The surface-attached initiator groups are subsequently used for the growth of surface-attached polymer chains in a surface-initiated polymerization reaction. It is shown that, while chlorosilanes require rather stringent exclusion of moisture during self-assembly, the hydridosilanes are rather robust and functional monolayers are formed even under ambient conditions. That in turn allows for the use of silanes in standard printing processes. In contrast to printing of chlorosilanes, which must be carried out under strictly anhydrous conditions, printing of hydridosilanes thus represents a simple and versatile technique for the generation of microstructured surfaces. © 2008 American Chemical Society.

Macromolecules

A robust method for the immobilization of polymer molecules on SiO 2 surfaces

Intermolecular and Surface Forces

Strong Intermolecular Forces

Effect of Cu(II) on the Kinetics of the Homogeneous Atom Transfer Radical Polymerization of Methyl Methacrylate

Polymer

Controlled grafting of a well-defined polymer on a porous glass filter by surface-initiated atom transfer radical polymerization

Amphiphilic Polymer Brushes Grown from the Silicon Surface by Atom Transfer Radical Polymerization

Synthesis, Characterization, and Properties of Tethered Polystyrene-b-polyacrylate Brushes on Flat Silicate Substrates

Polymer brushes via ATRP: Role of activator and deactivator in the surface-initiated ATRP of styrene on planar substrates

Journal	Macromolecular Rapid Communications
ISSN	10221336
Open Access	No