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Block copolymers having a pendant trichlorogermyl group as a part of polyamide segment(COR′CONHArNH)xCOR′COand polydimethylsiloxane of general formula [(COR′COHNArNH)xCOR′CONH(CH2)3SiO(CH3)2 ((CH3)2SiO)ySi(CH3)2(CH2)3 NH]n (where R′ = CH2CH(GeCl3), CH(CH3)CH(GeCl3), CH(GeCl3)CH(CH3); Ar = C6H4, (C6H3CH3)2, (C6H3OCH3)2, 2,5‐(CH3)2C6H2, C6H4OC6H4) were prepared by a polycondensation reaction and characterized using CHN and Ge analysis, Fourier transform infrared (FTIR) and 1H NMR spectroscopy, thermogravimetric analysis (TGA) and molecular weight determination. They have a lamellar structure with weight‐average molecular weight in the range 1.21 × 105–4.79 × 105 g mol−1. These copolymers display two glass transition temperatures and have an average decomposition temperature of 489 °C. TGA, FTIR and gas chromatography/mass spectrometry studies indicate that degradation of these block copolymers results in carbon monoxide, oligomeric siloxanes and polyamide fragments. They are thermally stable due to the hydrogen bonded interlinked chains of polyamide, while they absorb water due to the presence of GeCl bonding. Copyright © 2010 Society of Chemical Industry

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Layer-by-layer (LbL) assembled films have attracted attention as multicomposite conformal coatings either for the purpose of functionalizing surfaces with a large variety of different components or for the fabrication of electrical or optical thin-film devices. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] While most work on LbL films is based on electrostatic interactions, the use of covalent bonds has been reported as well. [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] Poly(dimethylsiloxane) (PDMS; Scheme 1), the most commonly used silicone-based organic polymer, is an elastomer whose unique molecular structure and physicochemical properties make it suitable for a broad range of applications, including lubricants, sealants, adhesives, eye contact lenses, microfluidic devices, or stamps for microcontact printing. [33] Although polyelectrolyte multilayers have been assembled on PDMS objects in various geometries, [34][35][36][37][38][39][40][41][42][43][44][45] there have not yet been any reports on the fabrication of multilayer films containing end-functionalized PDMS as a constituent. One of the reasons for a lack of experimental work in this area is most likely due to the fact that the end groups of polymers are notoriously difficult to react, firstly because the end groups constitute only a very small fraction of the chain and secondly because they are predominantly hidden inside the polymer coil for statistical reasons (Scheme 2, example on the right).The problem of end-group reactions is even more pronounced on surfaces than in solution because of the additional confinement in space. This difficulty for carrying out reactions on surfaces is well-known from much simpler related systems, for example, solid-phase peptide synthesis, in which incomplete yields of individual reaction steps may cause sequence defects in the final oligopeptide products.[46] If consecutive chemical reactions do not proceed with exactly 100 % yield, the surface density of available functional groups will decrease dramatically with an increasing number of reaction steps.A second important problem for fabricating multilayer films from homobifunctional reagents lies in the fact that backfolding of the second chain end followed by a reaction with the underlying reactive surface may further lead to a substantial decrease of functional groups available for attaching further layers. Although brush-like structures of Scheme 1. The two types of polymers used for covalent LbL deposition: 3-aminopropyl-terminated homobifunctional poly(dimethylsiloxane) (PDMS) with n % 34 and n % 364, and poly(ethylene-alt-maleic anhydride) (PEMA) with n % 800-4000. A monofunctional PDMS (PDMS-mono; not shown) with a single aminopropyl end group was also used.Scheme 2. Idealized depiction of the essential conformations of homobifunctional macromolecules attached to a surface by reactive chain ends. The red dots represent primary amino groups in this case, which react with anhydride groups present on the surface (not shown). Extended ...