Design of a new invertible polymer coating on a solid surface and its effect on dispersion colloidal stability.
This article presents a new approach to building up self-adjustable invertible polymer coatings at solid surfaces. The approach is based on a two-step process. In the first step, the surface of dispersed TiO2 or silicon wafers was functionalized with the aid of a reactive copolymer, viz., poly(styrene-alt-maleic anhydride) (PSM), to which, in the second step, the chains of amphiphilic oligoester have been tethered. The latter contains both hydrophilic poly(ethylene glycol) and hydrophobic aliphatic dibasic acid moieties being alternately distributed along the oligomer chains. It is shown that the titania modified in this way can form stable suspensions in both polar (water) and nonpolar (toluene) media. Moreover, multiple drying/redispersion cycles demonstrate the ability of the modified titania particles, after their removal from one type of dispersion and consequent drying, to be redispersed in dispersing media strongly differing by polarity from that of the previous medium. An environmentally induced switching of the surface properties has been observed via the measurement of the wetting contact angles and scanning force microscopy (SFM) of silicon wafers covered by PSM with tethered oligoester chains. These experiments give strong support for the predicted capability of such polymer coatings to switch their environmental appearance (i.e., to behave as a self-adjustable invertible interface because of the ability of the tethered amphiphilic oligoester chains to change their conformations in response to environmental changes in such a manner so as to adapt and enhance their compatibility with the surrounding media).
Kohut
A
A
Institute of Particle Technology, Friedrich Alexander University Erlangen-Nuremberg, Cauerstrasse 4, 91058 Erlangen, Germany.
Ranjan
S
S
Voronov
A
A
Peukert
W
W
Tokarev
V
V
Bednarska
O
O
Gevus
O
O
Voronov
S
S
D003102:Colloids / Q000737:chemistry*; D008298:Maleates / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D011137:Polystyrenes / Q000138:chemical synthesis / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
D003102:Colloids; D008298:Maleates; D011108:Polymers; D011137:Polystyrenes; C521900:poly(styrene-co-maleic anhydride); C009495:titanium dioxide; D014025:Titanium; D012825:Silicon