NMRP and ATRP Double Initiators for the Formation of Binary Polymer Brushes via Grafting-From Methods

Abstract

New ATRP and NMRP initiator molecules were synthesized, which were grafted on silica wafer surfaces and served for initiating the formation of polymer brushes via the grafting-from method. Two of the new initiators bore ATRP and NMRP moieties in the same molecule. These double initiators were used to produce binary polymer brushes with switchable surface properties: styrene was first polymerized via ATRP at 40 • C and 4-vinylpyridine was polymerized thereafter at 110 • C via NMRP. The brushes achieved in this way exhibited smooth surfaces differing in the thickness of the brush layers by less than 10% (at different areas of the wafers) and could be switched from hydrophobic to hydrophilic and vice versa.

Organic–inorganic hybrid functional materials by nitroxide-mediated polymerization

“…Besides, the authors showed that polymer chains with molar masses higher than 20 000 g mol -1 were quite stretched at the surface with a cross-sectional area per chain of, in average, 200 Å 2 (i.e., corresponding to around 0.8 chains/nm 2 ). Similar linear increase of brush thichness with molar mass were reported by Devaux et al [106,112] and others [107,108,110,[113][114][115][116][117][118][119]. In the former case, the polymer brushes were prepared by NMP of styrene initiated by trialkoxysilyl-terminated alkoxyamines previously deposited on the wafer surface using the Langmuir-Blodgett (LB) technique to enable the formation of very dense brushes.…”

“…As shown in Figure 7b, the lower the degree of chemical mistmach between the homopolymers and the grafted random copolymers, the lower was the interfacial energy (as determined from contact angle measurements), and the greater was consequently the polymer chains wetting ability. As said above, aside from this early work, the most common method for the synthesis of polymeric brushes onto flat silicon oxide surfaces is based on the use of the grafting from technique [99,[106][107][108][109][110][111][112][113][114][115][116][117][118][119][120].…”

“…Another strategy to control the morphology and properties of surface-tethered polymer chains is to randomly graft different kinds of homopolymers on a surface [107,108,110,111,118]. Such binary brushes have been extensively investigated both theoretically and experimentally and have been shown to behave differently from block copolymer brushes.…”

“…More recently, Thiessen et al [118] employed a similar dual initiator strategy to grow mixed binary PS/poly(4-vinylpyrine) (P4VP) polymer brushes on silicon wafers by successive ATRP of styrene and NMP of 4VP. The resulting brushes were shown to exhibit a reversibly switching hydrophobic/hydrophilic wetting behaviour upon alternatingly dipping the susbtrate in toluene and aqueous hydrochloric acid.…”

Solvent-free preparation, characterization, and properties of SEBS–g–polycarbonate copolymers

“…[5] The first one is the addition of a graft or block copolymer. [6][7][8][9][10][11][12] To form a graft copolymer, two strategies exist, the grafting from between polymers [13][14][15][16][17][18][19][20][21] and the grafting onto, [22][23][24][25][26][27][28][29] with a polymer bearing an initiating function previously induced by ozonolysis or irradiation. [30,31] A coupling reaction through a function can also be used to generate specific functions onto a polymer chain moiety to then start a grafting from or a grafting onto.…”