Cylindrical side-chain composition

In addition to the side chain conformation, chemically different side chains attached to the same main chain may also have a pronounced impact on the main chain conformation, particularly if the respective side chains are incompatible. Demixing of the side chain is hampered by the fact that the chemically different side chains are bound to the same main chain, leading to highly frustrated single chain structures. In order to experimentally address this point, the phase separation within statistical cylindrical brush copolymers comprising PMMA and poly-2-vinylpyridinium (PVP) side chains was investigated [93, 94]. The samples were prepared by radical copolymerization of methacryloyl end-functionalized PMMA M = 3,700 g/mol) and PVP M = 5,100 g/mol) macromonomers. Copolymer brushes with two different compositions were synthesized and characterized as shown in Table 1. Subsequent quatemization of the PVP side chains with ethylbromide was conducted in order to enhance incompatibiUty. 

The cyclic peptide approach to nanotubes has some advautages over all other methods. In addition to diameter control, one can highlight that the properties of the outer surface of the nanotube can easily be modified by varying the amino acid side chains. In addition, due to the Cn symmetry of the backbone skeleton, nonsymmet-rical CPs can form an infinite number of different SPN (Figure 23b). This phenomenon is based on the interstrand rotation between two consecutive CPs, to form nonequivalent interactions for each j8-sheet. Appropriate unit design and optimization of conditions for self-assembly allows the nanotube properties to be tailored for specific applications. As a result, SPN can be used as (or in) porous solid materials, soluble cylindrical supermolecules, ion channels and other transmembrane pores, soUd-supported ion sensors, antimicrobial and cytotoxic agents, and nanocluster composites. A recent review published by Granja et al. includes the most relevant examples in this area. ... 

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