Nanostructured surface INDEX

Keywords Nanostructures Surface plasmon resonance Localized surface plasmon resonance Bio-molecular interactions Refractive index change Effective medium Thin films Biosensors Sensitivity Nanoparticles... 

LSPR-based sensitivity enhancement using surface-relief nanostructures has been confirmed experimentally in a few smdies to date. In the experiments conducted by Byun et al. [26], ethanol-water mixture at varied ethanol concentration was used to estimate the sensitivity enhancement by periodic nanowires atA = 200 nm and 500 nm respectively as 44% and 31% over conventional structures, as shown in Fig. 7. Note that the sensitivity enhancement for bulk index measurement is relatively limited compared to layered bio-molecular interactions, because of reduced index contrast against ambience. It was also found that surface roughness can degrade sensitivity performance [27]. Measurement of the DNA hybridization process was performed using nanoposts at A = 110 run and presented more than fivefold sensitivity improvement, as shown in Fig. 8 [28]. 

Here, 1 examine the coupling of particle plasmons excited in nanoparticles with LSPs in surface relief nanostructures. As a biosensor, nanoparticles may serve as linker molecules that amplify the index change due to ligand bindings with... 

Three-dimensional PtRu nanostructures (i.e. PtgsRujs, 5.9 nm particle size Pt7gRu22, 6.7 nm) with defined shapes are available from Pt(acac)2 and Ru(acac)3 precursors . Capping of indexed surfaces using adamantaneacetic acid and hexadecylamine led to formation... 

Block polymers containing an etchable block have been used as precursors for nanoporous polymers [109]. Because nanoporous polymers have large internal surface areas, large pore volumes, and uniform pore dimensions, these materials were studied as separation/pmilication media, batteiy separators, templates for nanostructured materials, low dielectric materials, and low refractive index materials. Both pore wall functionality and robustness of the matrix are important for the practical use of nanoporous polymers. As shown in Eig. 5.16, PLA was selectively etched horn a blend with reactive block co-polymers to form a nanoporous material. 

Optofluidics refers to the complementary hybridization of photonics and fluidics. Optofluidic characterizatiOTi is the analysis of a fluidic system by photonics, and vice versa. In particular, nanoscale optofluidic characterization is related to photonic phenomena based on the nanostructures. The photonic band-gap properties, surface plasmon resonance, or surface-enhanced Raman scattering sensitively change with the refractive index of the surrounding fluid or the specific binding of chemicals and biomolecules on the nanostructures. 

The first observation of visible photoluminescence in nanostructured porous silicon (PS) at room temperature opened the possibilities of a wide range photovoltaic and photonic applications due to tunable refractive index and band gap, large surface/volume ratio, simplicity of fabrication technology, etc. (Canham 1997). Today porous silicon has become a very interesting and versatile material... 

In a distinct vein, BC/chitosan membranes have been tested for pervaporative separation of binary aqueous-organic mixtures (ethanol/water) [111]. The substantially high pervaporative separation index (350 kg. x.m. h 0 and low activation energy (10 kj.mol ) are indicative of the high potential of BC/chitosan membranes in the pervaporative separation of ethanol/water azeotrope. Targeting to mimic the intrinsic antimicrobial properties of chitosan on BC nanofibrils, nanostructured BC nanocomposite membranes were obtained by surface functionalization with aminoalkyl groups (Figure 2.14) [114]. These bioactive nanostructured membranes also presented improved mechanical and thermal properties and may be useful for biomedical applications. 

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