Polyferrocenyldimethylsilane

Scheme 3.8 Synthesis of polyferrocenyldimethylsilane- /e>d -polymethylmethacrylate via a chain-end switch from anionic to ATRP.

Figure 13 Cyclic voltammogram of polyferrocenyldimethylsilane 73 (R = = Me) in CH2CI2 (0.1 M of [Bu4N][PF6] in CH2CI2) at...

Cylindrical and tape-like morphologies have been identified in the case of PI-/ -PFS (PI = polyisoprene) where the PFS block crystallizes. " Water-soluble polyferrocenyldimethylsilane-/ -poly(aminoalkylmethacrylate) co-polymers of narrow polydispersity have also been prepared and cylindrical micelles have been identified. " Block co-polymers generated by transition metal-catalyzed ROP, such as PFS-/ -PDMS-/ -PFS triblock materials, have been shown to self-assemble in hexanes to yield a variety of remarkable architectures that include flower-like assemblies where the... 

Figure 1.9 (a) Phase separation of diblock copolymer (polystyrene-p-polyferrocenyldimethylsilane) guided by substrate strips (adapted from [39] with permission) (b) scheme of liquid-solid-solution (LSS) phase separation and transfer synthetic strategy (reproduced from [41] with permission). 

Synthesis and Self-Assembly of Polyisoprene-AtocA-Polyferrocenyldimethylsilane Diblock Copolymers Fabrication of Ceramic Nanolines on Semiconducting Substrates... 

Polyisoprene-Z)/oc -polyferrocenyldimethylsilane (PI-i-PFDMS) was synthesized by the anionic ring-opening polymerization of 1 initiated by living polyisoprene prepared inTHF (Scheme 1). The products were recovered as amber gumlike materials. 

The fitted multilayer thickness as a function of the number of deposited bUayers is shown in Figure 4, demonstrating that the thickness of the film is linearly related to the number of deposited bilayers, in accordance with the UV-Vis absorption spectroscopy results. The dashed line is a fit through the origin and indicates a thickness contribution of about 0.4 nm per bilayer. This result is influenced by the refractive index. Previously, combined ellipsometry and profilometry measurements led to a refractive index value of n=1.687 for spin-coated polyferrocenyldimethylsilane films on silicon wafers, and this value was also used for the polyferrocenylsilane multilayer thin films. However, the refractive index might be somewhat lower in this case, implying that the thickness contribution of 0.4 nm per bilayer we found could be a slight rmderestimate. 

Figure 2 Auger electron spectroscopy depth profile of an oxygen plasma-treated film of polyferrocenyldimethylsilane. The front of the image corresponds to the exposed fi-ee surface. (Reproduced with permission fi om Ref 48, 2001 ACS.)...

The pattern in Figure 3 demonstrates the potential of organometallic polymers as etch resists. The top half of the AFM image corresponds to the untreated pattern of polyferrocenyldimethylsilane (PFS). The bottom half displays the same pattern after it has been exposed to a CF4/O2 plasma treatment. 

Since the potential of polyferrocenyldimethylsilane as an etch barrier has been demonstrated above, we now want to focus on pathways to generate patterns of these polymers. Masking layers with such high etching resistance are potentially useful for very thin resist layer appUcations thin layers that prevent pattern collapse when fabricating high-aspect-ratio structures. 

Controlling the spontaneous formation of ordered domains in soft materials such as block copolymers [189] may lead to the development of stimuli-responsive materials for applications such as actuators [190] and photonics [191] due to the reversible nature of order formation. However, the stimuli that are typically used to control the morphology of block copolymers are e.g., temperature, pressure, solvent type and concentration... Pioneering work by Abbott and co-workers used the chemical oxidation approach to control the self-assembly of small-molecule amphiphiles containing ferrocene [192]. Rabin and co-workers have shown that the introduction of dissociated charges on one of the blocks of a diblock copolymer leads to stabilization of the disordered phase [193]. They also quantified the increase in x at the order-disorder transition (ODT), xodt, due to the entropic contribution of the dissociated counterions. The Flory-Huggins parameter,x, that is used to quantify interactions between polymer chains is assumed to be proportional to the difference in the polarizibility of the blocks [194]. The polarizibility of polyferrocenyldimethylsilane, which is larger than that of either polystyrene or polyisoprene [195], must increase upon oxidation due to the presence of the NO ions. 

Scheme 16.6 Synthesis of polyferrocenyldimethylsilane-Z -polydimethylaminoethylmethacylate. (Reproduced with permission from X.S. Wang, M.A. Winnik and I. Manners, Synthesis and aqueous self-assembly of a polyferrocenylsilane-block-poly(aminoalkyl methacrylate) diblock copolymer, Macromolecular Rapid Communications, 2002,23, 210. Wiley-VCH Verlag GmbH Co. KGaA.).

Scheme 16.8 Synthesis of polyferrocenyldimethylsilane-Z -polymethylmethacrylate via chain end mediation using DPE.

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