Laser Light Scattering Observations of Liquid–Liquid Phase Separation in a Polymer-Induced Liquid-Precursor (PILP) Mineralization Process

2005 ◽  
Vol 873 ◽  
Author(s):  
Elaine DiMasi ◽  
Tianbo Liu ◽  
Matthew J. Olszta ◽  
Laurie B. Gower
Keyword(s):  
Light Scattering ◽  
Calcium Carbonate ◽  
Liquid Phase ◽  
Laser Light ◽  
Early Stage ◽  
Liquid Droplet ◽  
Laser Light Scattering ◽  
Scattering Data ◽  
Droplet Growth ◽  
Liquid Precursor

AbstractA Polymer-Induced Liquid-Precursor (PILP) process for mineralization of calcium carbonate has been studied in-situ by laser light scattering. Static and dynamic light scattering data were obtained from CaCl2 solutions containing poly(aspartic acid). Under these conditions calcium carbonate mineralizes through a liquid droplet precursor phase when the solution is exposed to the decomposition products of ammonium carbonate. Our measurements probe the integrated scatterer mass and the apparent hydrodynamic radius Rh,app of the droplets as they nucleate and coalesce. The data reveal three stages in the formation of the PILP phase: an early stage of droplet growth to Rh,app ≈ 250 nm; a mid-time stage of fluctuations and polydispersity in particle size; and a final growth period where Rh,app increases from 350 nm to the micron scale. Aggregation of precursor droplets, rather than atom-by-atom growth, is the dominant mechanism of mineral formation under these conditions. With respect to biomineralization, this first observation of 100-nm-scale droplets is significant, implying a possibility to mineralize from the liquid phase within the nanoscale compartments in which many biominerals form.

Natural colloid characterization using flow-field-flow-fractionation followed by multi-detector analysis

1998 ◽  
Vol 37 (6-7) ◽  
pp. 173-180 ◽  
Author(s):  
Frank v. d. Kammer ◽  
Ulrich Förstner
Keyword(s):  
Light Scattering ◽  
Ionic Strength ◽  
Flow Field ◽  
Laser Light ◽  
Driving Forces ◽  
Relevant Information ◽  
Laser Light Scattering ◽  
Scattering Data ◽  
Field Flow Fractionation ◽  
Flow Fractionation

A design for a flow-field-flow-fractionation with UV/VIS-, fluorescence- and laser-light-scattering-detectors is presented and tested with extracts from a humus rich horizon of a gleyic podzol. It is tested to show how the system can retrieve relevant information about changes in the constitution of the colloid samples. The main objective is the investigation of colloid alteration during processes provoked by main geochemical driving forces (e.g. pH or ionic strength), in this case changes of redox potential. Therefore fluorescence- and UV/VIS-fractograms are taken at different wavelengths and compared. Particle diameters of natural colloids are calculated from laser-light-scattering data and compared with reference standards.

The Use of Laser-Light Scattering and Controlled Shear in Platelet Aggregometry

1991 ◽  
Vol 65 (05) ◽  
pp. 601-607 ◽  
Author(s):  
Jeffrey A Hubbell ◽  
Phillip I Pohl ◽  
William R Wagner
Keyword(s):  
Light Scattering ◽  
Laser Light ◽  
Platelet Rich Plasma ◽  
Cylindrical Tube ◽  
Aggregate Size ◽  
Complete Recovery ◽  
Laser Light Scattering ◽  
Scattering Data ◽  
Platelet Aggregometry ◽  
Induced Aggregation

SummaryLaser-light scattering was used to observe and quantify the dynamics of human blood platelet aggregation in platelet-rich plasma (PRP). Aggregation was performed in a controlled shear environment by placing the PRP in the annular space between a rotating cylindrical rod and a stationary cylindrical tube. The instrument was capable of very sensitive continuous semi-quantitative measurements of chemically-induced microaggregation. As a demonstration of the technique, results are presented for ADP-induced aggregation at doses of 10, 1, and 0.1 μM and collagen-induced aggregation at a dose of 5 μg/ml, each at shear rates of 1,000 s-1 and 500 s-1. Extensive aggregation was observed in response to ADP at even the low dose of 0.1 μM, indicating a high sensitivity to microaggregates. The sensitivity of the ultimate size of the ADP-induced aggregates to ADP concentration was shear dependent. The formation of microaggregates by collagen stimulation was shown to be almost immediate, as contrasted with a 10-20 s typical lag when observed turbidometrically. Disaggregation was observed with 1 μM ADP, but this was only partial, as contrasted with the complete recovery of transmittance observed in the turbidometric technique. Electronic particle sizing and counting was employed to semiquantitatively verify the aggregate size distributions found from mathematical conversion of the laser-light scattering data.

In-Situ Dual-Wavelength Ellipsometry and Light Scattering Monitoring of Si/Si1−xGex Heterostructures and Multiuantum Wells

1993 ◽  
Vol 324 ◽  
Author(s):  
C. Pickering ◽  
D.A.O. Hope ◽  
W.Y. Leong ◽  
D.J. Robbins ◽  
R. Greef
Keyword(s):  
Growth Rate ◽  
Light Scattering ◽  
Laser Light ◽  
Growth Period ◽  
Laser Light Scattering ◽  
Heterojunction Bipolar Transistor ◽  
Dual Wavelength ◽  
Multi Quantum Well ◽  
Refractive Index Data

AbstractIn-situ dual-wavelength ellipsometry and laser light scattering have been used to monitor growth of Si/Si1−x,Gex heterojunction bipolar transistor and multi-quantum well (MQW) structures. The growth rate of B-doped Si0 8Ge0.2 has been shown to be linear, but that of As-doped Si is non-linear, decreasing with time. Refractive index data have been obtained at the growth temperature for x = 0.15, 0.20, 0.25. Interface regions ∼ 6-20Å thickness have been detected at hetero-interfaces and during interrupted alloy growth. Period-to-period repeatability of MQW structures has been shown to be ±lML.

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