Nanoparticles
http://www.4spe.org/plastics-encyclopedia/perylene-nanoparticles"In nanotechnology, a particle is defined as a small object that behaves as a whole unit in terms of its transport and properties. It is further classified according to size: in terms of diameter, fine particles cover a range between 100 and 2500 nanometers, while ultrafine particles, on the other hand, are sized between 1 and 100 nanometers. Similar to ultrafine particles, nanoparticles are sized between 1 and 100 nanometers. Nanoparticles may or may not exhibit size-related properties that differ significantly from those observed in fine particles or bulk materials. Although the size of some molecules would fit into this range, individual molecules are usually not referred to as nanoparticles."
(Wikipedia, Nanoparticles, 12/7/2010)
“Techniques for producing nano-particles include: mechanical, chemical or thermal processing. In mechanical processes, nanopowders are commonly made by crushing techniques such as ball milling. There are several disadvantages to this approach. The grinding media and the mill wear away and combine with the nanomaterial, contaminating the final product. Additionally, nano-particles produced by ball milling tend to be non-uniform in size and shape and have a wide distribution of particle sizes. “
“Chemical processes can be used to create nanomaterials through reactions that cause particles to precipitate out of a solution, typically by reduction of organo-metallic materials. Such methods can produce powders contaminated by unreacted materials such as carbon. Additionally, precipitation tends to form large particles and agglomerates rather than nano-scale particles. “
“Thermal processes utilize vaporization and quenching phases to form nano-scale particles. Such known processes have accomplished vaporization using techniques such as joule heating, plasma torch synthesis, combustion flame, exploding wires, spark erosion, ion collision, laser ablation and electron beam evaporation. Plasma torch synthesis tends to produce particles with a wide distribution of particle sizes as do exploding wire and combustion flame synthesis. Ion collision and electron beam evaporation tend to be too slow for commercial processes. Laser ablation has the disadvantage of being extremely expensive due to an inherent energy inefficiency. Joule heating has been used in the past to create metal vapors that were condensed to nanomaterials in rapidly flowing turbulent quench gases. This process produces particles with a large size distribution, uses large quantities of gas, and is difficult to scale to commercial bulk production.”
(Carpenter, US Patent 7,803,295, 9/28/2010)
Aerosols
Carbon Black
Cellulose Nanoparticles
Chitosan Nanoparticles
Core-Shell Nanoparticles
Exfoliated Clay /Nanoclay
Iron Oxide Nanoparticles
Imprinted Nanoparticles
Janus Particles
J Aggregates
Liposomes
Magnesium Hydroxide Nanoparticles
Magnetic Nanoparticles
Materials
Micelles
Nanoparticle Drug Delivery
Nanoparticle Fabrication
Nanoparticle Safety
Nanoparticle Surfaces
Perylene Nanoparticles
Polythiophene Nanoparticles
Quantum Dots
Radiation Induced Pulverization
Self-Assembly of Nanoparticles
Silver (Ag) Nanoparticles
Starch Nanopaticles
Templating Nanoparticles
Viruses
Recent US Patents
9/20/2011
8,021,582
Method for producing microparticles in a continuous phase liquid
Lee and Chen of National Cheng Kung University, Taiwan, enable a continuous phase liquid and a dispersed phase liquid to flow together through a co-flow channel. Preferably, the dispersed phase liquid is arranged to flow within the flowing body of the continuous phase liquid in the co-flow channel so that the dispersed phase liquid is sheathed by the continuous phase liquid. The continuous phase and dispersed phase liquids are comminuted into microparticles in the co-flow channel by intermittently blocking the co-flow channel. (RDC 9/23/2011)
Recent Journal Articles
On the Apparent SEC Molecular Weight and Polydispersity Reduction upon Intramolecular Collapse of Polydisperse Chains to Unimolecular Nanoparticles
(8644–8649) Macromolecules 44 #21 (2011)
Pomposo et al, Spain, found that when unimolecular particles of molecular weight M are formed by intramolecular cross-linking of individual polymer chains, a significant reduction in hydrodynamic radius and, hence, apparent molecular weight (Mapp) by size exclusion chromatography (SEC) with traditional calibration. Two limiting cases provide the expected minimum and maximum β values: β ≈ 0.56 for perfectly compact nanoparticles and β ≈ 1 for nano-objects equivalent to flexible chains in good solvent. (RDC 11/3/2011)
Functionalization of shaped polymeric nanoobjects via bulk co-self-assembling gelable block copolymers with silane coupling agents
(3681-3686) Polymer 52 #17 (2011)
Gao, Zhang and Chen of the Chinese Academy of Sciences, China, obtained hairy polymer nanoobjects (PNOs) of different shapes by cross-linking the discontinuous microphases of bulk block copolymers followed by dispersing in a solvent. Herein we report a general approach to functionalize the shaped PNOs by bulk microphase separation of poly(3-(triethoxysilyl)propyl methacrylate)-block-polystyrene (PTEPM-b-PS) copolymers in the presence of functional silane coupling agents. The silanes like (3-mercaptopropyl)trimethoxysilane and (3-chloropropyl)trimethoxysilane were enriched into the PTEPM discontinuous microdomains selectively. For the PTEPM78-b-PS348 which had a lamellar structure, its blending mixtures with MMS and CMS whose content reached up to 50 wt% still remained as a lamellar structure. When small amount of MMS or CMS was added, the PTEPM71-b-PS780 as hexagonally packed cylinders remained its structure. However, the morphology changed into lamellae at higher content of the silanes. For PTEPM46-b-PS1669, its spherical structure remained but the size distribution became broad gradually with increase of silanes. By inducing gelation and then dispersing in a good solvent of PS phases, hairy PNOs having lamellar, cylindrical or spherical shape with their cores being functionalized with the groups from co-gelated silanes were obtained. (RDC 8/4/2011)
Review Articles
The chemical engineering of low-dimensional materials
(1104–1118)AIChE Journal 57 #5 (2011)
Paulus et al of Massachusetts Institute of Technology, Massachusetts, reviewed the properties of low dimensional materials in which one or more dimensions are on the nanometer scale. These include single wall carbon nanotubes and graphene. (RDC 5/5/2011)