Aggregation Behavior of Na-Neutralized Styrene-Ran-Methacrylic Acid Copolymers in Aqueous Solution

The aggregation behavior of un-neutralized, partly and fully Na-neutralized poly(styrene-ranmethacrylic acid) copolymers in aqueous solution was investigated using a SEM technique. It was observed that the un-neutralized copolymer formed spherical particles on the Si wafer, and the average size of particles was ca. 160 nm. The particle sizes did not change much with acid content. Upon the neutralization of the acid groups of the copolymer with NaOH, the copolymer became more hydrophilic, leading to the formation of network-like feature consisting of much smaller particles (<50 nm), compared to those of the acid copolymers. With increasing ionization, the boundary of the particles forming networks faded away, implying the formation of tubular structures.

Download Full-text

Room-temperature synthesis of submicron platinum and palladium powders in glycols

Journal of Materials Research ◽

10.1557/jmr.1999.0500 ◽

1999 ◽

Vol 14 (9) ◽

pp. 3707-3712 ◽

Cited By ~ 10

Author(s):

K. Tekaia-Elhsissen ◽

F. Bonet ◽

S. Grugeon ◽

S. Lambert ◽

R. Herrera-Urbina

Keyword(s):

Size Distribution ◽

Room Temperature ◽

Spherical Particles ◽

Average Particle ◽

Particle Sizes ◽

Temperature Synthesis ◽

Bimodal Size Distribution ◽

Hydrazine Reduction ◽

Average Size ◽

Palladium Particles

Platinum and palladium powders with average particle sizes in the submicron range have been synthesized at room temperature by hydrazine reduction of and , respectively, in glycols. Platinum powders contain spherical particles with a bimodal size distribution. Palladium powders also contain spherical particles, but the size distribution is narrow. The effect of both ammonia and hydrazine concentration on the size distribution and average size of palladium particles was investigated.

Download Full-text

Microstructure and Interconnections Characteristics of Titanium Foam

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.687.25 ◽

2016 ◽

Vol 687 ◽

pp. 25-32 ◽

Cited By ~ 2

Author(s):

Krzysztof Pałka ◽

Grzegorz Adamek ◽

Jarosław Jakubowicz

Keyword(s):

Particle Size ◽

Chemical Reactions ◽

Open Porosity ◽

Spherical Particles ◽

Particle Sizes ◽

High Permeability ◽

Titanium Particle ◽

Average Size ◽

Titanium Foam ◽

To Receive

Titanium foams are widely used as biomaterials and potentially as a twin skinned, sandwich, structures for aerospace structures, filter or a catalyst or catalysts carrier for chemical reactions. The porosity is particularly important for tissues ingrowth and vascularity. Open porosity is essential in the case of flow-on machines. The distribution and size of pores is significant to achieve a uniform material effort and ensure to receive an appropriate hydraulic properties.The aim of this study was to determine the effect of titanium particle size and the amount of porogen on the microstructure and the size of pore interconnections in titanium foams made using saccharose as the space holder material.The paper characterizes titanium foam, made from the Grade 1 Ti powders (Alfa Aesar) with a particle sizes of 0.150 mm and 0.044 mm (separately) and spherical particles of saccharose (Pfeifer & Langen) having an average size of 0.7 ÷ 0.9 mm, as a porogen. There was prepared a mixture of powders of the proposed porosity of 50, 60 and 70%. Summarizing 6 mixtures were prepared. After sintering there were received specimens having a diameter of 8 mm and a height of 5 mm. Microstructure analysis was performed using the microtomography Skyscan 1172 (Bruker microCT) and the CTAn software (Bruker microCT).The results indicate the uniform pore distribution and size of the interconnections allowing high permeability.

Download Full-text

Preparation of BSA Nanoparticles by Desolvation Technique Using Acetone as Desolvating Agent

International Journal of Pharmaceutical Sciences and Nanotechnology ◽

10.37285/ijpsn.2012.5.1.8 ◽

2012 ◽

Vol 5 (1) ◽

pp. 1643-1647

Author(s):

Krishna Sailaja A ◽

Amareshwar P

Keyword(s):

Aqueous Solution ◽

Standard Deviation ◽

Process Parameters ◽

Self Assembly ◽

Size Control ◽

Polymeric Materials ◽

Preparation Condition ◽

Assembly Process ◽

Average Size

In order to see the functionality and toxicity of nanoparticles in various food and drug applications, it is important to establish procedures to prepare nanoparticles of a controlled size. Desolvation is a thermodynamically driven self-assembly process for polymeric materials. In this study, we prepared BSA nanoparticles using the desolvation technique using acetone as desolvating agent. Acetone was added intermittently into 1% BSA solution at different pH under stirring at 700 rpm. Amount of acetone added, intermittent timeline of acetone addition, and pH of solution were considered as process parameters to be optimized. The effect of the process parameters on size of the nanoparticles was studied. The results indicated that the size control of BSA nanoparticles was achieved by adding acetone intermittently. The standard deviation of average size of BSA nanoparticles at each preparation condition was minimized by adding acetone intermittently. The intermittent addition in polymeric aqueous solution can be useful for size control for food or drug applications.

Download Full-text

Influences of subphase pH and temperature on the interfacial aggregation behavior of poly(lauryl methacrylate)-block-poly(methacrylic acid)

Colloids and Surfaces A Physicochemical and Engineering Aspects ◽

10.1016/j.colsurfa.2021.126528 ◽

2021 ◽

pp. 126528

Author(s):

Kun Jiang ◽

Gangyao Wen ◽

Athanasios Skandalis ◽

Stergios Pispas ◽

Yanping Ding ◽

...

Keyword(s):

Methacrylic Acid ◽

Aggregation Behavior

Download Full-text

Upconversion Luminescence of Silica–Calcia Nanoparticles Co-doped with Tm3+ and Yb3+ Ions

Materials ◽

10.3390/ma14040937 ◽

2021 ◽

Vol 14 (4) ◽

pp. 937

Author(s):

Katarzyna Halubek-Gluchowska ◽

Damian Szymański ◽

Thi Ngoc Lam Tran ◽

Maurizio Ferrari ◽

Anna Lukowiak

Keyword(s):

Energy Transfer ◽

Near Infrared ◽

Upconversion Luminescence ◽

Sol Gel ◽

Emission Spectra ◽

Transmission Electron ◽

Characteristic Emission ◽

Diffraction Patterns ◽

Size Of Particles ◽

Average Size

Looking for upconverting biocompatible nanoparticles, we have prepared by the sol–gel method, silica–calcia glass nanopowders doped with different concentration of Tm3+ and Yb3+ ions (Tm3+ from 0.15 mol% up to 0.5 mol% and Yb3+ from 1 mol% up to 4 mol%) and characterized their structure, morphology, and optical properties. X-ray diffraction patterns indicated an amorphous phase of the silica-based glass with partial crystallization of samples with a higher content of lanthanides ions. Transmission electron microscopy images showed that the average size of particles decreased with increasing lanthanides content. The upconversion (UC) emission spectra and fluorescence lifetimes were registered under near infrared excitation (980 nm) at room temperature to study the energy transfer between Yb3+ and Tm3+ at various active ions concentrations. Characteristic emission bands of Tm3+ ions in the range of 350 nm to 850 nm were observed. To understand the mechanism of Yb3+–Tm3+ UC energy transfer in the SiO2–CaO powders, the kinetics of luminescence decays were studied.

Download Full-text