Nanoconfinement effects

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. 

Ellison CJ, Mundra MK, Torkelson JM (2005) Impacts of polystyrene molecular weight and modification to the repeat unit structure on the glass transition-nanoconfinement effect and the cooperativity length scale. Macromolecules 38 1767-1778... 

Dielectric analysis can also be used to study nanoconfinement effects in the polymer chains contained in a polymer blend. Here, the most reasonable... 

Zhu et al. and Huang et al. employed a block copolymer/homopolymer system (poly(ethylene oxide)-h-polystyrene/polystyrene) in order to study the crystallization of PEO under hard and soft confinement [180, 244]. In a related work, Xu et al. prepared blends of poly(oxyethylene)-h-poly(oxybutylene) and polystyrene/poly(oxybutylene) and compared confined versus breakout crystallization [249, 308]. Guo et al. studied a block copolymer/thermoset blend constituted by poly(ethylene)-h-poly(ethylene oxide)/bisphenol A type epoxy resin. The authors reported the nanoconfinement effect on the crystallization kinetics of the PE block [309]. 

The exploration on the generality of nanoconfinement effects on glassy dynamics beyond thin films and nanocomposites could help obtain a more complete... 

Kim, S., Mundra, M.K., Roth, C.B., Torkelson, J.M. Suppression of theTg-nanoconfinement effect in thin poly(vinyl acetate) films by sorbed water. Macromolecules 43, 5158 (2010)... 

On the other hand, the reader is reminded that the magnitude of the depression in the glass transition temperature of polycyanurate networks under nanoscale constraint may be attributable to two effects 1) the nanoconfinement effect observed for glass-formers confined to the nanoscale [1-7], and 2) an increased probability of side reactions such as monomer cyclization... 

This paper presents the curing of bisphenol M dicyanate ester under nanoscale constraint. The effects of pore size and pore surface chemistty on the evolution of glass transition temperature of polycyanurate netwoiks are investigated and both are found to have a significant effect on the curing behavior and final Tf. Nanoconfinement accelerates the cure of bisphenol M dicyanate. For the unsilanized CPG, both the nanoconfinement and surface effects are observed whereas for the silanized controlled pore glass, only the nanoconfinement effect is present. FTIR study confirms the full conversion of the polycyanurate networks under nanoscale confinement. 

A schematic of the flow-through nanohole array concept is shown in Fig. 13a. Figure 13b shows computationally predicted biomarker transport within the nanoholes for in-hole average fluid velocities of 1 pm/s and 1 cm/s (as indicated). Reaction rate constants characteristic of surface-based antibody-antigen reactions (with reaction rate constant k - 10 /M/s) [69] were applied at the nanohole walls. For the low average velocity, diffusion of the biomarker (with diffusivity D - 4x10 m s ) to the nanohole surface is effectively complete in one diameter. This result reflects the rapid diffusion characteristic of nanoconfinement. For the higher flow rate case, the absorption of the analyte stream is delayed however, over 90% bulk adsorption of analyte is attained with the flow rates and nanohole... 

Bou-Malham I, Bureau L (2010) Nanoconfined ionic liquids effect of surface charges on flow and molecular layering. Soft Matter 6(17) 4062 065. doi 10.1039/c0sm00377h... 

Nanostructured materials obtained by sol-gel encapsulation of biomolecules are a novel class of biomaterials. The biological macromolecules, confined within the nanometer-size pores of the matrix, show both similarities to and differences from solution characteristics. The effects of nanoconfinement on the structural and reactivity patterns of the proteins and enzymes are discussed. The applications of these nanostructured biomaterials in the area of molecular biorecognition, detection, and biosensing are also presented. 

The paper is organized in three parts. First, the effects of nanoconfinement on the structure of the sol-gel trapped biomolecule are discussed. Second, from the results on apparent reactivity of these biomaterials, the effects of the matrix on the reactivity of trapped enzyme are elucidated. Finally, the interaction of the confined biomolecules with exogenous ligands/substrates and the applications of these materials in the area of molecular biorecognition are discussed. The reaction chemistries of biologically active molecules in die nanostructured materials have been crucial in establishing the role of the matrix upon the structure and reactivity of the confined proteins. 

In addition to these chemical effects, physical effects due to nanoconfinement within a pore of finite dimension should adso be taken into consideration. Upon treatment of sol-gel confined enzyme with an exogenous substrate, the substrate... 

Table IL Effects of Nanoconfinement on Biopartide Structure and Reactivity...

Discrete analysis of the complicated dynamics in complex polymer systems and nanocomposites, especially of the anomalies of the glass transition behavior in these materials, including the interfacial dynamics. Characterization of the dynamic modes within a broad glass transition range caused by the nanoconfinement and constrained dynamics effects. 

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