Multifunctional Nanostructure

Figure 19.3 Schematic view of the multifunctional nanostructure photoreleasing NO and 102...

J. Kim, Y. Piao, and T. Hyeon, Multifunctional nanostructured materials for multimodal imaging, and simultaneous imaging and therapy, Chem. Soc. Rev., 38 (2009) 372-390. 

One-step electropolymerization deposition processes are envisaged as the most interesting deposition methods in view of potential technological applications. For this reason, there is a growing interest in the integration of materials obtained in such way to obtain multifunctional nanostructured composites and hybrid materials. The selective localization through electrophoretic deposition of nanotubes at the interface of polymers to obtain flexible, transparent and conductive materials could represent a novel approach. 

The primary objective of this report is a mix and match approach towards innovative classes of multifunctional nanostructured composites and hybrid materials. Such materials are expected to stimulate evolutionary advances and revolutionary breakthroughs in emerging key technology areas. 

I. Armentano, N. Bitinis, E. Fortunati, S. Mattioli, N. Rescignano, R. Verdejo, M. Lopez-Manchado, and J. Kenny, Multifunctional nanostructured PLA materials for packaging and tissue engineering, Prog. Polym. Sci., 38,1720-47,2013. 

Faustini, M., Nicole, I., Boissiere, C., Innocenzi, P., Sanchez, C, and Grosso, D. (2010) Hydrophobic, antireflective, self-cleaning, and antifogging sol-gel coatings an example of multifunctional nanostructured materials for photovoltaic cells. Chem. Mater, 22, 4406-4413. 

An alternative route to disulfide formation is a thiol-disulfide exchange reaction [160, 167, 168] in the presence of a 2,2 -dipyridyl disulfide(or derivative) as a reactive disulfide. Two very recent studies revealed that the thiol-disulfide exchange reaction (pathway c in Scheme 5) offers better selectivity and control over the disulfide formation process. Moreover, the obtained mixed disulfide remains reactive towards thiols for further modification. In contrast to the above-described amine-thiol-ene conjugation, this approach is not 100% atom-efficient because 2-mercaptopyridine (or a derived structure) is released in the reaction medium. Monteiro and coworkers synthesized multifunctional nanostructures (worms and rods) with multiple chemical functionalities directly in water using a one-step RAFT-dispersion polymerization. The introduced functional handles originate from their presence in the R group on the CTA. In the case of thiolactone worms and rods, aminolysis with allylamine and subsequent one-pot scavenging of... 

As template pores can range from the macro- (>50 nm diameter) to the meso- (2-50 nm diameter) and even to the micropore (<2 nm diameter) range, there is still a lot to be learned about migration through these pores of the active ions dnring electrodeposition. A detailed knowledge of the dynamics of this diffusion, so called ionics in these pores, can extend the ability to create multifunctional nanostructures in these pores throngh electrodeposition. 

The nanostructured molecular arrangements from DNA developed by Seeman may find applications as biological encapsulation and drug-delivery systems, as artificial multienzymes, or as scaffolds for the self-assembling nanoscale fabrication of technical elements. Moreover, DNA-protein conjugates may be anticipated as versatile building blocks in the fabrication of multifunctional supramolecular devices and also as highly functional-... 

The concept of bifnnctionality can be snitably expanded (Scheme 1) to prodnce multifunctional catalysts bearing both diverse nanostructured metals and diverse chemical functionalities for performing complementary catalytic tasks. 

The main difference between titania nanotube and the ID nanostructures discussed before is the presence of an hollow structure, but which has significant consequences for their use as catalytic materials (i) in the hollow fiber nanoconfinement effects are possible, which can be relevant for enhancing the catalytic performance (ii) due to the curvature, similarly to multi-wall carbon nanotubes, the inner surface in the nanotube is different from that present on the external surface this effect could be also used to develop new catalysts and (iii) different active components can be localized on the external and internal walls to realize spatially separated (on a nanoscale level) multifunctional catalysts. 

Debra Rolison (right) was born in Sioux City, Iowa in 1954. She received a B.S. in Chemistry from Florida Atlantic University in 1975 and a Ph.D. in Chemistry from the University of North Carolina at Chapel Hill in 1980 under the direction of Prof. Royce W. Murray. She joined the Naval Research Laboratory as a research chemist in 1980 and currently heads the Advanced Electrochemical Materials section. She is also an Adjunct Professor of Chemistry at the University of Utah. Her research at the NRL focuses on multifunctional nanoarchitectures, with special emphasis on new nanostructured materials for catalytic chemistries, energy storage and conversion, biomolecular composites, porous magnets, and sensors. 

A substrate functionalized with proper molecules can be used to anchor particles on its surface via surface exchange reaction, leading to controlled assembly of the particles. This self-assembly technique is known as molecule-mediated self-assembly and is commonly used for constructing various composite nanostructures [49-55]. Due to their excellent adhesion capability to various substrates, multifunctional polymers are routinely applied as templates to mediate the assembly of the particles. The assembly is carried out as follows a substrate is immersed into a polymer solution, and then rinsed, leading to a functionalized substrate. Subsequently, this substrate is dipped into the nanoparticle dispersion and then rinsed, leaving one layer of nanoparticles on the substrate surface. By repeating this simple two-step process in a cyclic fashion, a layer-by-layer assembled poly-mer/nanoparticle multilayer can be obtained. 

Electrodes and solid catalysts applied in the synthesis of chemicals or in emission control are, generally, hierarchical systems comprising dimensions ranging from millimeter to nanometer scale, allowing for mass and heat transport within a reactor, molecular transport of reactants and products through a pore system, and chemical reactions on nanostructured, frequently multifunctional surface sites as illustrated in Figure 4.2.2. Catalyst preparation always yields a catalyst precursor, whereas the active phase is only formed in contact with the feed of the substrate molecules in... 

---