Polymer nanostructures molecules

FIGURE 7.3 Schematic illustration showing how functional molecules can induce a self-assembly route to conducting polymer nanostructures. 

This approach mimics in some way dye sensitized solar cells because porphyrin/fuUerene clusters serve as sensitizers for buffer tin oxide (Sn02). At the same time, mixed fuUerene/polymer nanostructures resemble bulk heterojunction solar cells since donor (porphyrin) and acceptor (fullerene) molecules are blended together in the active layer. 

Polymer Nanostructure Active molecule Potential application References... 

D. J. Klein and A. T. Balaban, Clarology for conjugated carbon nanostructures Molecules, polymers, graphene, defected graphene, fractal henzenoids, fullerenes, nanotuhes, nanocones, nanotori, etc.. Open Org. Chem. J. (Suppl. 1-M3) (2011) 27-61. 

Another detailed and recent description of the diffusion processes for molecules released from polymer nanofibers is based on the desorption-limited theory of admixture release.In this case, the release is mainly driven by desorption, or dissolution, from nanopores on the surface of the polymer nanostructures. To describe this mechanism, one firstly defines a so-called nanoporosity factor, Np, as the ratio of the initial amount of drug admixture on the nanofiber surface, nisur/O), and the total initial amount of drug loaded in the nanofibers, mp(0) [i.e. the drug molecules on the surface plus those in the... 

Physical encapsulation systems use polymer nanostructures as formulation systems, and the polymer can have different uses. It may prevent dissolution or it may control diffusion. Polymers that delay drug dissolution slow the rate at which drug molecules are exposed to water from the aqueous environment surrounding the DDS. This may be achieved by using a polymer coating or a matrix that dissolves at a slower rate than the drug [30-32]. 

DNA is ideally suited as a structural material in supramolecular chemistry. It has sticky ends and simple rules of assembly, arbitrary sequences can be obtained, and there is a profusion of enzymes for modification. The molecule is stiff and stable and encodes information. Chapter 10 surveys its varied applications in nanobiotechnology. The emphasis of Chapter 11 is on DNA nanoensembles, condensed by polymer interactions and electrostatic forces for gene transfer. Chapter 12 focuses on proteins as building blocks for nanostructures. 

P. Kumar, A. Mehta, S.M. Mahurin, S. Dai, M.D. Dadmun, B.G. Sumpter, and M.D. Barnes, Formation of oriented nanostructures from single molecules of conjugated polymers in microdroplets of solution the role of solvent, Macromolecules, 37 6132-6140, 2004. 

These novel carbon nanostructures can also be modified by (a) doping, that is the addition of foreign atoms into the carbon nanostructure, (b) by the introduction of structural defects that modify the arrangement of the carbon atoms and (c) by functionalization involving covalent or noncovalent bonding with other molecules. These modifications opened up new perspectives in developing novel composite materials with different matrices (ceramic, polymer and metals). For example, polymer composites containing carbon nanostructures have attracted considerable attention due to... 

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