Hairy polymers

In most cases, the adsorbing surface is tacitly assumed to be completely inert and nonresponsive to protein attachment. This assumption may be valid for surfaces of crystalline material but in the case of hairy polymer surfaces, changes in the polymer surface conformation due to the presence of adsorbed protein may be expected. 

Hairy polymer colloids formed in this way might find application in several domains in the future. With a polymer brush exhibiting a LCST, the change of surface properties with temperature could be of high interest for appUcations based on adsorption-desorption processes, such as their use as stationary phases for bioseparation. Recently, PEG-based N-substituted acrylamide maeromonomers were grafted via SI-ATRP from the surface of polystyrene latexes. These PEG-based surfaces showed good protection against nonspecific protein adsorption from... 

A unique but widely studied polymeric LB system are the polyglutamates or hairy rod polymers. These polymers have a hydrophilic rod of helical polyglutamate with hydrophobic alkyl side chains. Their rigidity and amphiphilic-ity imparts order (lyotropic and thermotropic) in LB films and they take on a F-type stmcture such as that illustrated in Fig. XV-16 [182]. These LB films are useful for waveguides, photoresists, and chemical sensors. LB films of these polymers are very thermally stable, as was indicated by the lack of interdiffusion up to 414 K shown by neutron reflectivity of alternating hydrogenated and deuterated layers [183]. AFM measurements have shown that these films take on different stmctures if directly deposited onto silicon or onto LB films of cadmium arachidate [184]. 

A cell-wall polysaccharide fraction remaining after treatment with a "classical" pectinase is termed rhamnogalacturonan (RG) or modified hairy regions (MHR). It is characterized by a highly branched ihamnogalacturonan-polymer with some arabinan side chains. 

FIGURE 5.7 Schematic Representation of typical, (partially) electroluminescent LC polymer architectures. (a) Rodlike structure, (b) Hairy-rod structure, (c) Combined main-chain-side-chain system, (d) Semiflexible segmented structure, (e) Semiflexible segmented structure with disklike mesogen. (After Weder, C. and Smith, P., Main-chain liquid-crystalline polymers for optical and electronic devices, in Encyclopedia of Materials Science and Technology, Buschow, K.H., Cahn, R.W., Flemings, M.C., Ilschner, B., Kramer, E.J., and Mahajan, S., Eds., Elsevier Science, New York, 2001.)... 

Makki-Ontto R, de Moel K, de Odorico W, Ruokolainen J, Stamm M, ten Brinke G, Ikkala O. Hairy tubes mesoporous materials containing hoUow self-organized cylinders with polymer brushes at the walls. Adv Mater 2001 13 117-121. 

Hairy rigid rod polymers, in which flexible side chains are attached to a rigid core, present attractive properties [9.155]. A supramolecular version of such materials may be the triple helical supramolecular species described above (Figure 41), which presents the features of a hairy cylinder. Similarly, the components 176 and 177 bearing long R chains yield self-assembled, supramolecular hairy rigid rods. 

Fig. 7.23 Self-assembled hairy-rod polymers based on metal coordination and ionic interaction.

We close this section by examining the status of applications of these methods to polymer monolayers. Initially, ISR was used to probe the 2D nematic state of phthalocyaninatopolysiloxane, descriptively called a hairy rod , dispersed in eicosanol [ 149], and subsequently applied to a set of poly(f-butyl methacrylate) in the semi-dilute regime and beyond [150]. In the semi-dilute regime, the surface viscosity is found to scale linearly with molecular weight, which is in good accord with the results of Sacchetti et al. [134]... 

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