b-PEO)3 three-arm star block copolymer allowed the easy cross-linking of the PB segments

directly at the A/W interface without any additives or reagents. This strategy permits to control

the size of the PEO pores simply by adjusting the surface pressure during cross-linking as shown

by AFM imaging of the LB films.

 Further characterization of these 2D cross-linked networks will be required (gas

permeability, small angle scattering, and 2D viscometry) to understand the benefits provided by

the A/W interfacial self-assembly compared to other conventional solution self-adsorption or

other processes. At stake is the possibility to use 2D self-organization as a means to construct

materials with anisotropic structures, to reproducibly engineer such structures, and to target

defined functions with these materials. In addition, such alkoxysilane-containing monolayers

could also be easily grafted onto inorganic surfaces (glass support such as silicon wafer) through

covalent bonds to synthesize polymer/inorganic composite materials.

 5.4 Experimental Methods

5.4.1 Materials and Instrumentation

 The synthesis of the PB-b-PEO three-arm star block copolymers was previously

reported.222 Toluene used in the hydrosilylation reactions was dried and distilled twice over CaH2

and polystyryllithium successively. The PB homopolymer (2r = 11,050 g/mol; 2y/2, = 1.04)

(Polymer Source Inc.), triethoxysilane (Aldrich, 99%), and platinum(0)-1,3-divinyl-1,1,3,3-

tetramethyldisiloxane complex (Karstedt catalyst, 3 wt % solution in xylene) (Aldrich, 99%)

were used as received without further purification. 1H-NMR spectra were recorded on Varian-

VXR 300 MHz, Gemini 300 MHz, and Mercury 300 MHz using CDCl3 aS the deuterated

solvent. Chemical shifts are reported in ppm (6) downfield from tetramethylsilane (TMS) and

referenced to residual chloroform (7.27 ppm). FTIR absorbance spectra were recorded on a

Bruiker/Vector 22 FT/IR spectrometer. The samples were prepared by dissolving the