Sidechain functionalized polymers

Keywords Block copolymers Hydrocarbon membranes Proton exchange membranes Sidechain functionalized polymers Sulfonated poly(arylene ether)s ... 

Copolymerization reactions with ferrocenophanes using transition metal catalysts have also been accomplished. The self-assembly of block copolymers has been examined, and polymers with dimethylsiloxane or ethyleneoxide blocks have been found to be soluble in aqueous solution. These ferrocene-based polymers have been found to self-assemble in solution, and their morphologies have been investigated. A number of water-soluble anionic (26) and cationic (27) polyelectrolytes have also been produced by sidechain functionalization. 

We have reported that norbornene monomers functionalized with arene complexes also undergo ring-opening metathesis polymerization to produce the corresponding cyclopentadienyliron-coordinated polynorbomenes. Scheme 13 shows the synthesis of polymers containing aromatic ether sidechains functionalized with organoiron moieties. ... 

Results indicate that the effectiveness of quaternary ammonium salt polymers in stabilizing swelling clays and mineral fine particles is dependent on monomer chemical structure and polymer molecular weight. Long flexible pendant sidechains containing quaternary nitrogen atoms appear to be required for these polymers to function as mineral fine particle stabilizers. 

While it may be expected that the interchain separation will be a function of the length of the pendant sidechain, the relation is unlikely to be linear. For example, folding becomes more likely with an increasing number of constituents in the methylene chains connecting the urethane functional group to the polymer spine. Upper bounds on the interchain distances for the PDAs investigated are given in Table II. 

Fig. 3.2.4 [Wiel] Orientation dependent C NMR spectra of the liquid crystalline sidechain polymer (a) before (b) and after (c) irradition with light. The shaded regions are C resonances from nuclei in natural abundance. The angle measures the orientation of optical axis of the film relative to the magnetic field Bo- (d) Moments of the orientational distribution function before and after inadition.

Perfluorinated ionomers such as Nafion are of significant commercial importance as cation exchange membranes in brine electrolysis cells ( 1). Outstanding chemical and thermal stability make this class of polymers uniquely suited for use in such harsh oxidizing environments. The Nafion polymer consists of a perfluorinated backbone and perfluoroalkylether sidechains which are terminated with sulfonic acid and/or carboxylic acid functionality. 

This EVB model was employed to the systematic study of model pores or channels. Taking a simphstic view, the polymer was regarded as a rigid framework in which slab or cylinder pores of constant thickness or radius, respectively, are formed. Within this approach, proton transport in pores has been studied as a function of a variety of generic structural and dynamical features of the polymer and operational parameters of the working fuel cell (such as temperature and humidity). These studies revealed a number of factors determining the proton mobihty, such as the width of the channel, distance between the sidechains, and their flexibility. The main lessons of the simulations and the theoretical analysis were ... 

The polymerization of 1,2,3-substituted ferrocenes containing one iodo and one acetlyene group using Sonogashira coupling resulted in the production of polymers with functionalized sidechains (11). The reaction of l,l -diiodoferrocene with diethynyl monomers has also been used in the production of polymetaUocenes with semiconducting properties (12). "... 

The polycondensation of acetylene-substituted metallocenes has yielded polymers containing backbone aUcyne bridges. The synthesis of l-iodo-2-methoxy-methyl-3-ethynylferreocene and l-iodo-2-(N,N-dimethylamino methyl)-3-ethynyl-ferreocene was reported by Plenio and coworkers. Polymerization of these ferrocene-based complexes gave rise to soluble bimodal 1,3-linked ferrocene-acetylene polymers. Polymers exhibiting optical activity or functionalized sidechains were produced via Sonogashira coupling reactions. 

PyAG-12 in the bulk as a function of temperature. The phase occurring at temperatures below 25°C was described as a layered struchue with the polypeptide chain in the P-sheet conformation and the alkyl sidechain crystallized in a separate phase with a periodicity of 24 A. The high temperature phase appeared in the proximity of 125°C and was thought to be a nematic phase with the a-helix polypeptide packed in a hexagonal array. Nothing was said about the structure adopted by the polymer at intermediate temperatures. 

One strategy to improve the adhesion between a substrate and a functional coating is the establishment of a covalent chemical bond between the polymer molecules, of which the functional layer consists, and the surface of the substrate. Most approaches in that direction use polymers carrying an anchor group either as an end-group or in a sidechain, which can be reacted with appropriate sites at the substrate surface yielding surface-attached monolayers ( grafting to ) [8-12], Such a chemisorption process is in some aspects closely related to the... 

In the following we describe two selected systems where the polymer monolayers carry functional groups—polyelectrolyte brushes and sidechain liquid crystal brushes. 

A second example for the synthesis of a functional surface-attached polymer brush is the preparation of monolayers of a liquid-crystalline polymer (TCP) with mesogenic units in the sidechain [43]. Such a system could be of interest for the preparation of alignment layers for liquid-crystal displays (LCD) [44,45]. Alignment layers are key components for the production of LCDs [46-50]. As the orientation of the nematic director of the LC in contact with a surface is energetically degenerate, domains are formed in the LC layer that lower the contrast of the display. Thin films of polymers such as rubbed polyimide film ( alignment layers ) are frequently used to align the liquid-crystalline molecules in order to form extended monodomains. 

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