scholarly journals Controlled Shape and Porosity of Polymeric Colloids by Photo-Induced Phase Separation

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1225
Author(s):  
Elad Hadad ◽  
Eitan Edri ◽  
Hagay Shpaisman
Keyword(s):  
Phase Separation ◽  
Polyethylene Glycol ◽  
Chemical Composition ◽  
Particle Shape ◽  
Polymer Concentration ◽  
Continuous Phase ◽  
Uv Curable ◽  
Profound Influence ◽  
Acetone Water ◽  
Kinetics Of

The shape and porosity of polymeric colloids are two properties that highly influence their ability to accomplish specific tasks. For micro-sized colloids, the control of both properties was demonstrated by the photo-induced phase separation of droplets of NOA81—a thiol-ene based UV-curable adhesive—mixed with acetone, water, and polyethylene glycol. The continuous phase was perfluoromethyldecalin, which does not promote phase separation prior to UV activation. A profound influence of the polymer concentration on the particle shape was observed. As the photo-induced phase separation is triggered by UV radiation, polymerization drives the extracted solution out of the polymeric matrix. The droplets of the extracted solution coalesce until they form a dimple correlated to the polymer concentration, significantly changing the shape of the formed solid colloids. Moreover, control could be gained over the porosity by varying the UV intensity, which governs the kinetics of the reaction, without changing the chemical composition; the number of nanopores was found to increase significantly at higher intensities.

Spinodal Decomposition in Fe-Cr-Co Alloys

1982 ◽  
Vol 21 ◽  
Author(s):  
S. S. Brenner ◽  
P. P. Camus ◽  
M. K. Miller ◽  
W. A. Soffa
Keyword(s):  
Phase Separation ◽  
Spinodal Decomposition ◽  
Atom Probe ◽  
Continuous Phase ◽  
Miscibility Gap ◽  
Two Phase ◽  
Probe Field ◽  
Long Wavelength ◽  
Composition Fluctuations ◽  
Kinetics Of

Continuous phase separation or spinodal decomposition occurs within a miscibility gap through the selective amplification of long wavelength concentration waves to produce a two-phase modulated microstructure. To comprehensively study the formation of these modulated microstructures and the kinetics of continuous phase separation the behavior of the composition fluctuations in the decomposing material should be monitored directly. The atom probe field-ion microscope is an ideal instrument for this type of investigation of fine-scale microstructures because of its ultra-high spatial resolution and microchemical analysis capability.

Kinetics of phase separation for polyethylene glycol-phosphate two-phase systems

1995 ◽  
Vol 48 (3) ◽  
pp. 246-256 ◽  
Author(s):  
A. Kaul ◽  
R. A. M. Pereira ◽  
J. A. Asenjo ◽  
J. C. Merchuk
Keyword(s):  
Phase Separation ◽  
Polyethylene Glycol ◽  
Two Phase ◽  
Phase Systems ◽  
Kinetics Of

Kinetics of the α-α′ phase separation in a 14%Cr oxide dispersion steel at intermediate temperatures

2020 ◽  
pp. 129088
Author(s):  
Yael Templeman ◽  
Malki Pinkas ◽  
Eli Brosh ◽  
Einat Strumza ◽  
Shmuel Hayun ◽  
...  
Keyword(s):  
Phase Separation ◽  
Oxide Dispersion ◽  
Α Phase ◽  
Kinetics Of

Phase Separation of β-SN in Strained, Compositionally Metastable Ge1-xSnx Alloys

1995 ◽  
Vol 398 ◽  
Author(s):  
Joshua W. Kriesel ◽  
Susanne M. Lee
Keyword(s):  
Phase Separation ◽  
Electron Microprobe ◽  
Rf Sputtering ◽  
Melting Behavior ◽  
Solubility Limit ◽  
X Ray Diffraction ◽  
Solid Solubility Limit ◽  
Transformation Mechanisms ◽  
Subsequent Phase ◽  
Kinetics Of

ABSTRACTUsing rf sputtering and post-deposition annealing in a differential scanning calorimeter (DSC), we manufactured bulk (4000 nm) films of crystalline Ge0.83Sn0.17. This Sn concentration is much greater than the solid solubility limit of Sn in Ge (x ≤ 0.01). Continued annealing thermally induces Sn phase separation from the alloy, limiting the ultimate attainable grain size in the metastable crystals. We examine, here, the mechanisms and kinetics of the processes limiting the size of the Ge0.83Sn0.17 polycrystals. From a combination of DSC, electron microprobe, and x-ray diffraction (XRD) measurements, we propose phase transformation mechanisms corresponding to crystallization of amorphous Ge0.83Sn0.17, crystallization of an as-yet unidentified phase of Sn, and phase separation of Sn from the Ge1-xSnx crystals. We were unable to observe the unidentified phase of Sn in XRD, but the phase must be present in the material to account for the quantitative discrepancies (as much as 8 at.%) in Sn percentages determined from each of the DSC, XRD, and electron microprobe measurements. Our models for the various transformation kinetics were corroborated by the subsequent phase-separated Sn melting behavior observed in the DSC: two Sn melting endotherms, one of which was 20–100°C lower than the bulk melting temperature of Sn. This depressed temperature endotherm we speculate represents liquefaction of nanometer-sized (β–Sn clusters.

scholarly journals Thermodynamics and kinetics of phase separation of protein-RNA mixtures by a minimal model

2021 ◽  
Vol 120 (7) ◽  
pp. 1219-1230 ◽  
Author(s):  
Jerelle A. Joseph ◽  
Jorge R. Espinosa ◽  
Ignacio Sanchez-Burgos ◽  
Adiran Garaizar ◽  
Daan Frenkel ◽  
...  
Keyword(s):  
Phase Separation ◽  
Minimal Model ◽  
Thermodynamics And Kinetics ◽  
Kinetics Of

scholarly journals Mixing state and compositional effects on CCN activity and droplet growth kinetics of size-resolved CCN in an urban environment

2012 ◽  
Vol 12 (21) ◽  
pp. 10239-10255 ◽  
Author(s):  
L. T. Padró ◽  
R. H. Moore ◽  
X. Zhang ◽  
N. Rastogi ◽  
R. J. Weber ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Water Soluble ◽  
Anthropogenic Sources ◽  
Droplet Growth ◽  
Mixing State ◽  
Aerosol Composition ◽  
Activation Kinetics ◽  
Aerosol Mixing State ◽  
Kinetics Of ◽  
Ccn Activity

Abstract. Aerosol composition and mixing state near anthropogenic sources can be highly variable and can challenge predictions of cloud condensation nuclei (CCN). The impacts of chemical composition on CCN activation kinetics is also an important, but largely unknown, aspect of cloud droplet formation. Towards this, we present in-situ size-resolved CCN measurements carried out during the 2008 summertime August Mini Intensive Gas and Aerosol Study (AMIGAS) campaign in Atlanta, GA. Aerosol chemical composition was measured by two particle-into-liquid samplers measuring water-soluble inorganic ions and total water-soluble organic carbon. Size-resolved CCN data were collected using the Scanning Mobility CCN Analysis (SMCA) method and were used to obtain characteristic aerosol hygroscopicity distributions, whose breadth reflects the aerosol compositional variability and mixing state. Knowledge of aerosol mixing state is important for accurate predictions of CCN concentrations and that the influence of an externally-mixed, CCN-active aerosol fraction varies with size from 31% for particle diameters less than 40 nm to 93% for accumulation mode aerosol during the day. Assuming size-dependent aerosol mixing state and size-invariant chemical composition decreases the average CCN concentration overprediction (for all but one mixing state and chemical composition scenario considered) from over 190–240% to less than 20%. CCN activity is parameterized using a single hygroscopicity parameter, κ, which averages to 0.16 ± 0.07 for 80 nm particles and exhibits considerable variability (from 0.03 to 0.48) throughout the study period. Particles in the 60–100 nm range exhibited similar hygroscopicity, with a κ range for 60 nm between 0.06–0.076 (mean of 0.18 ± 0.09). Smaller particles (40 nm) had on average greater κ, with a range of 0.20–0.92 (mean of 0.3 ± 0.12). Analysis of the droplet activation kinetics of the aerosol sampled suggests that most of the CCN activate as rapidly as calibration aerosol, suggesting that aerosol composition exhibits a minor (if any) impact on CCN activation kinetics.

Phase-separation kinetics of a multicomponent alloy

1999 ◽  
Vol 60 (2) ◽  
pp. 822-830 ◽  
Author(s):  
S. Mazumder ◽  
D. Sen ◽  
I. S. Batra ◽  
R. Tewari ◽  
G. K. Dey ◽  
...  
Keyword(s):  
Phase Separation ◽  
Multicomponent Alloy ◽  
Phase Separation Kinetics ◽  
Kinetics Of ◽  
Separation Kinetics
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