scholarly journals Colloidal Probes of PNIPAM-Grafted SiO2 in Studying the Microrheology of Thermally Sensitive Microgel Suspensions

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jing Shang ◽  
Ruonan Gao ◽  
Fu Su ◽  
Huaguang Wang ◽  
Dan Zhu

The complex rheology and the phase behavior of thermally sensitive poly(N-isopropylacrylamide) (PNIPAM) microgels have been investigated in both the swollen and collapsed states by using microrheology. To avoid the interactions between the tracer probes and the PNIPAM microgels, such as the adsorption or the depletion effect, the probes of silica (SiO2) particles have been grafted with PNIPAM chains (SiO2-PNIPAM) and characterized with Fourier transform infrared spectroscopy (FTIR). The successful preparation of SiO2-PNIPAM has also been proved by the investigation of the particle size and morphology with dynamic light scattering (DLS) and transmission electron microscope (TEM) below and beyond the phase transition temperature of PNIPAM. The microrheology of the PNIPAM microgel suspension has been investigated by using the prepared SiO2-PNIPAM particles as microrheological probes, and the results show that the diffusive coefficient of the probes in the swollen state is one-fifth of that in the collapsed state, and the viscosity of the PNIPAM microgel suspension in the swollen state is four times higher than that in the collapsed state, indicating SiO2-PNIPAM is a good probe in the microrheological study of PNIPAM microgel suspensions.

2006 ◽  
Vol 61 (12) ◽  
pp. 1566-1572 ◽  
Author(s):  
Dongsheng Li ◽  
Sridhar Komarneni

Platinum nanoparticles and nanorods were synthesized by microwave-assisted solvothermal techniques. Changing the reaction conditions controlled particle size and morphology. The effects of the reaction conditions, such as the molar ratio of the polyvinylpyrrolidone (PVP) repeating unit to the metal sources, the concentration of metal sources, the reaction temperature, and the presence of distilled water were investigated. Nanoparticles of Pt were approximately 3 nm in size. Produced nanoparticles and nanorods were characterized by transmission electron microscopy. Image JTM software was used to calculate the particle size and size distribution.


2014 ◽  
Vol 1058 ◽  
pp. 15-19 ◽  
Author(s):  
Sheng Jie Yang ◽  
Feng Gao ◽  
Meng Jie Qin ◽  
Qing Qing Zhang ◽  
Xi Xi Huang

Plate-like Sr3Ti2O7powders with anisotropy were prepared by KCl molten salt synthesis (MSS) method, the effect of different SrCO3/TiO2ratio and calcination condition on the phase transition, particle size and morphology of powders were investigated. The results show that SrTiO3phase coexist with Sr3Ti2O7phase and SrTiO3is the main phase as the SrCO3/TiO2ratio is 1.15~1.25:1. Pure Sr3Ti2O7phase can be obtained as the SrCO3/TiO2ratio is 1.55~1.65:1. The aspect ratio of plate-like particles increases firstly and then decreases as the SrCO3/TiO2ratio increases. The sealed and unsealed condition has no influence on the phase structure of the powders. But the aspect ratio of unsealed particles is smaller than that of sealed particle. Finally, the formation mechanism for Sr3Ti2O7particles was discussed.


2008 ◽  
Vol 8 (8) ◽  
pp. 3930-3935 ◽  
Author(s):  
Dongsheng Li ◽  
Sridhar Komarneni

Well-dispersed Pd nanoparticles were synthesized by microwave-assisted solvothermal technique using methanol and ethanol. Particle size and morphology were controlled mainly by the reaction temperature. Particle size of Pd nanoparticles was controlled in the range of 2 to 11 nm by manipulating the reaction conditions. The Pd nanoparticles were characterized by transmission electron microscopy for particle size and shape and UV-Vis spectroscopy for optical properties. UV-Vis spectra showed that synthesized Pd nanoparticles stabilized with PVP had absorption bands at around 280 to 290 nm.


2011 ◽  
Vol 415-417 ◽  
pp. 648-651 ◽  
Author(s):  
Bing Xu ◽  
Ren Guo Song ◽  
Chao Wang

Ag, Au and Ti metal nanoparticles colloids have been prepared by pulsed laser ablation in various liquids. The particle size and morphology of the obtained nanoparticles colloids were characterized by transmission electron microscopy (TEM), the average diameter and its distribution were analyzed by Image-ProPlus software. The results showed that the Au nanoparticles were of the best characterization, the average diameter was the smallest (D=8.79 nm), and also, the distribution of particle size was the narrowest (=17.5 nm) and the morphologies were more homogeneous.


RSC Advances ◽  
2015 ◽  
Vol 5 (18) ◽  
pp. 13331-13340 ◽  
Author(s):  
T. N. Ng ◽  
X. Q. Chen ◽  
K. L. Yeung

Flow-synthesis of mesoporous silica allows deliberate and precise control over the size and shapes and enables the preparation of complex microstructures (i.e., hollow spheres).


2021 ◽  
Vol 11 (14) ◽  
pp. 6578
Author(s):  
Aleksandra Jedlińska ◽  
Alicja Barańska ◽  
Dorota Witrowa-Rajchert ◽  
Ewa Ostrowska-Ligęza ◽  
Katarzyna Samborska

This paper discusses the physicochemical properties of powders obtained by spray drying of cloudy beetroot juice, using dehumidified air in variants with or without carriers. The inlet air temperature was 130 °C or 90 °C, and the addition of the carriers was at a ratio of juice to carrier solids of 3:2. In the obtained powders, the following physicochemical properties were determined: water content and water activity, apparent density, loose and tapped density, porosity, flowability, particle size and morphology, and the content and retention of betalains. It was possible to dry cloudy beetroot juice without the use of carriers at low temperatures (90 or 130 °C). The 100% beetroot powders were characterized by satisfactory physicochemical properties, often better than those with carriers (including lower hygroscopicity and higher color saturation and yield). A lower loss of betalains was found for the powders with the addition of carriers. The best process yields were obtained for the powder without carriers at 130 °C and 90 °C.


2015 ◽  
Vol 14 (04) ◽  
pp. 1550013 ◽  
Author(s):  
Urvisha Tarpara ◽  
Poorvesh Vyas ◽  
Mihir J. Joshi

Calcium tartrate finds various applications. In the present study, calcium tartrate nanoparticles were synthesized by wet chemical method using surfactant mediated approach. The powder XRD pattern revealed the typical broadening of peaks indicating the nanostructured nature. The average crystallite size was calculated by applying the Scherrer's formula to powder XRD pattern and was found in the range of 22.8–23.9 nm. The particle size and morphology of the synthesized nanoparticles was confirmed by using transmission electron microscopy (TEM). FTIR spectroscopy was used to confirm the presence of various functional groups. From TGA, it was found that calcium tartrate nanoparticles remained stable up to 120°C and were having two water molecules associated with them. The results are compared with the bulk crystalline materials available in the literature.


2007 ◽  
Vol 336-338 ◽  
pp. 140-142
Author(s):  
Jun Jie Hao ◽  
Xiao Hui Wang ◽  
Shi Yun Lin ◽  
Long Tu Li

Na0.5Bi0.5TiO3 (NBT) is considered to be an excellent candidate for lead-free piezoelectric ceramics. In this study, we propose a hydrothermal method for the preparation of single phase NBT powder at relatively low treatment-temperature. The particle size and morphology of the synthesized powders were examined by SEM. The powders were further pressed into disk and sintered at 1120°C/2h in air, and its properties and microstructure were compared with traditionally prepared samples.


2014 ◽  
Vol 2 (37) ◽  
pp. 15437-15447 ◽  
Author(s):  
Aziz Abdellahi ◽  
Oncu Akyildiz ◽  
Rahul Malik ◽  
Katsuyo Thornton ◽  
Gerbrand Ceder

Using calculations based on first principles, we demonstrate that the preferred interface in singles LiFePO4 particles depends both on the particle size and morphology.


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