In situ synthesis of high-density contact-free Ag-nanoparticles for plasmon resonance polystyrene nanocomposites
(7905-7911) Journal of Materials Science 46 #24 (2011)

Site-Specific Placement of Au Nanoparticles on Chemical Nanopatterns Prepared by Molecular Transfer Printing Using Block-Copolymer Films
(3074–3082)Advanced Functional Materials 21  #16 (2011)
Onses et al of the University of Wisconsin-Madison, Wisconsin, transferred patterns of hydroxyl-terminated poly(styrene) brushes  from poly(styrene-block-methyl methacrylate) (PS-b-PMMA) block copolymer films onto a replica substrate via molecular transfer printing and the remaining areas are filled with hydroxyl-terminated poly(2-vinyl pyridine) (P2VP-OH) brushes.  Citrate-stabilized Au NPs (13 nm) selectively bind to P2VP-OH functionalized regions and the quality of the resulting assemblies depends on high chemical contrast in the patterned brushes.  Minimization of the interpenetration of P2VP-OH chains into PS brushes during processing is the key for achieving high chemical contrast. Large area hexagonal arrays of single Au NPs with a placement accuracy of 3.4 nm were obtained on patterns (20 nm spots, 40 nm pitch) derived from self-assembled cylinder-forming PS-b-PMMA films. Linear arrays of Au NPs were generated on patterns (40 nm lines, 80nm pitch) derived from lamellae-forming PS-b-PMMA that had been directed to assemble on lithographically defined masters.  (RDC 8/15/2011)

Anisotropic particles with different morphologies of silver nanoshell: Synthesis and optical properties
(340-344) Colloid Journal 73 #3 (2011)
Kartseva et al pf the Russian Academy of Sciences, Russia, synthesized hydrosols of spindle-shaped composite particles with the core of iron(III) oxyhydroxide and silver shell by enlarging metal seeding nanoparticles adsorbed on the surface of the cores in the solution containing silver nitrate and mild reducing agent.  It is revealed that the character of the growth of shells on gold seeding particles greatly depends on the type of reducing agent.  When using ascorbic acid, seeding particles grow primarily in the direction normal to the core surface due to the blocking of some of the particle faces by ions present in the solution.  As a result, the forming shell is characterized by a fairly nonuniform structure.  At the same time, when using formaldehyde, the growth of seeding nanoparticles proceeds predominantly in the lateral direction to form first an island-like film, then a continuous thin metal shell on the core surface.  It is demonstrated that the position of localized surface plasmon resonance of such structure can be fine tuned to the preset wavelength by controlled variations in the thickness of Ag shell with very small step (up to 1 nm). (RDC 8/2/2011)

Tandem synthesis of silver nanoparticles and nanorods in the presence of poly(oxyethylene)-amidoacid template
( 1383-1389) European Polymer Journal 47  #7 (2011)
Dong, Tsai and Lin of National Taiwan University and National Chung Hsing University, Taiwan, carried out sequential formation of silver nanoparticles (AgNPs) and nanorods from the reduction of AgNO3 was affected by a poly(oxyethylene)-amidoacid (POE-amidoacid) in aqueous solution.   The requisite POE-amidoacid, consisting of –(CH2CH2O)n– segments with amide and carboxyl groups, was simply prepared via amidation with trimellitic anhydride of a poly(oxyethylene)-monoamine (POE-amine) of molecular weight (Mw) 2000 g/mol. The POE-amidoacid afforded AgNPs as small as 5 nm in diameter, which gradually (over a period of months) self-assembled into nanorods that were 10–15 nm in width and 30–50 nm in length. The hierarchical formation of Ag species occurred only at ambient temperature, but Ag aggregates formed above 50 °C.  Fourier transform infrared (FTIR) and tapping-mode atomic force microscopy (TM-AFM) analyses revealed that the structurally tailored POE-amidoacid was indeed multifunctional: it reduced Ag+, stabilized the obtained Ag0 species, and served as a template for the tandem formation of AgNPs and nanorods.  (RDC 6/27/2011)

Influence of Various Reduction Reagents on the Morphological Properties of Ag Nanoparticles@Silk Fiber Prepared Using Sonochemical Method
(369-375)  Journal of Inorganic and Organometallic Polymers and Materials 21  #2 (2011)
Abbasi and Morsali of Tarbiat Modares University, Iran, prepared silk fiber-containing Ag nanoparticles through chemical reduction under ultrasound irradiation.  The influence of reducing reagents on the morphological properties of the Ag nanoparticles-silk fiber was studied. The size of the metallic nanoparticles vary significantly with the type of reducing reagent used in the synthesis. A strong reducing reagent promotes a fast reaction rate and favors the formation of smaller nanoparticles. A weak reducing reagent induces a slow reaction rate and favors relatively larger particles. (RDC 5/23/2011)

Preparation of silver nanoparticles on cellulose nanocrystals and the application in electrochemical detection of DNA hybridization
 (67-74) Cellulose 18 #1 (2011)
Liu, Wang, Song and Shang of China synthesized Ag nanopaticles with carboxylated cellulose nanocrystals as the scaffolds by reducing metallic cations using NaBH4.  Ag particles with a size less than 10 nm were readily prepared and well dispersed.  The carboxyl and hydroxyl groups of carboxylated cellulose nanocrystals supplied a coordination effect to adsorb metallic cations and Ag nanoparticles, which prevent the aggregation of nanoparticles. The carboxylated cellulose nanocrystals carrying Ag nanoparticles were used as labels for electrical detection of DNA hybridization.  (RDC 2/11/2011)

Silver nanoparticles on titanate nanobelts via the self-assembly of weak polyelectrolytes: synthesis and photocatalytic properties
(# 085705) Nanotechnology 22 #8 (2010)
Bračko et al of the Jožef Stefan Institute, Solvenia used a weak-polyelectrolyte multilayer on a surface of titanate nanobelts (Ti-NBs) as a template for in situ Ag nanoparticle formation in the fabrication of Ag-loaded Ti-NBs nanocomposites.  The polyelectrolyte multilayer (PEM) was fabricated using layer-by-layer self-assembly of poly(acrylic acid) (PAA) and poly(allylamine hydrochloride) (PAH) on the surface of high-surface-area titanate nanobelts (Ti-NBs) synthesized using a hydrothermal procedure.  The subsequent annealing of the Ag/Ti-NBs–PEM nanocomposites yielded nanostructured crystalline Ag/Ti-NBs. An enhanced UV photo-efficiency was observed for the Ag/Ti-NBs nanocomposites compared with pure Ti-NBs. As-fabricated Ag(x)/Ti-NBs nanocomposites also exhibited visible photoactivity assisted by the near-field amplitudes of the localized surface plasmon resonance (LSPR) of the silver nanoparticles in the 1D nanocomposite.  (RDC 1/21/2011)

Assembly, characterization of Ag nanoparticles in P(AAm-co-NVP)/CS semi-IPN, and swelling of the resulting composite hydrogels
(181-199) Polymer Bulletin 65 #2 (2010)
Xu, Chen and Jia produced silver nanoparticles with controlled size and size distribution by an in situ chemical reduction route based on a microreactor template composed of poly(acrylamide-co-N-vinylpyrrolidone)/chitosan semi-interpenetrating network hydrogels, P(AAm-co-NVP)/CS semi-IPN, in the presence of sodium hypophosphite.  The Ag grains were uniformly dispersed within the  hydrogel networks in a spherical shape, and were stabilized by the semi-IPN structure and a complexation and/or electrostatic interaction between Ag+ cations and chemical functional groups, such as –OH, –CONH2, –NH2 or –C=O based on the semi-IPN structure reactor templates. The size of the majority of AgNPs ranges from 12 to 25 nm, depending on the three-network templates, the presence of functional groups as well as feed ratios of N-vinylpyrrolidone, acrylamide, and chitosan.   (RDC 12/16/2010)