Crystal aggregation into periodically grating-banded assemblies in phthalic acid modulated by molten poly(ethylene oxide)

CrystEngComm ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 467-477 ◽  
Author(s):  
Tzu-Yu Chen ◽  
Eamor M. Woo ◽  
Selvaraj Nagarajan
Keyword(s):  
Ethylene Oxide ◽  
Small Molecule ◽  
Phthalic Acid ◽  
Ordered Structures ◽  
Crystal Aggregation ◽  
Banded Spherulites ◽  
Small Molecule Compound ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

A small-molecule compound, phthalic acid (PA), crystallized in the presence of poly(ethylene oxide) (PEO) with various compositions was utilized as a model to investigate the morphology and crystal assembly of periodically ordered structures in banded spherulites.

Poly(ethylene) oxide for small-molecule crystal growth in gelled organic solvents

2011 ◽  
Vol 44 (1) ◽  
pp. 172-176 ◽  
Author(s):  
Duane Choquesillo-Lazarte ◽  
Juan Manuel García-Ruiz
Keyword(s):  
Crystal Growth ◽  
Ethylene Oxide ◽  
Small Molecules ◽  
Organic Solvents ◽  
Small Molecule ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

The use of poly(ethylene) oxide (PEO) as a gelator has been evaluated with a selected list of organic solvents. From the 26 solvents tested, eight formed gel matrices. This number was extended to 19 when poly(ethylene) oxide was used with a mixture of solvents. The procedure for the preparation of PEO organogels is described, and their application for the crystallization of small molecules using different crystallization techniques in the presence of organic solvents is discussed.

The Structure of Radiation Cross-Linked Poly (ethylene oxide) Gels

1971 ◽  
Vol 29 ◽  
pp. 76-77
Author(s):  
C. E. Cluthe ◽  
G. G. Cocks
Keyword(s):  
Molecular Weight ◽  
Ethylene Oxide ◽  
Parallel Plate ◽  
Average Molecular Weight ◽  
Radical Reaction ◽  
Free Radical Reaction ◽  
Nitrogen Gas ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Initial Viscosity

Aqueous solutions of a 1 weight-per cent poly (ethylene oxide) (PEO) were degassed under vacuum, transferred to a parallel plate viscometer under a nitrogen gas blanket, and exposed to Co60 gamma radiation. The Co60 source was rated at 4000 curies, and the dose ratewas 3.8x105 rads/hr. The poly (ethylene oxide) employed in the irradiations had an initial viscosity average molecular weight of 2.1 x 106.The solutions were gelled by a free radical reaction with dosages ranging from 5x104 rads to 4.8x106 rads.

Preparation of Organized Mesoporous Silica from Sodium Metasilicate Solutions in Alkaline Medium Using Nonionic Surfactants

2003 ◽  
Vol 68 (10) ◽  
pp. 2019-2031 ◽  
Author(s):  
Markéta Zukalová ◽  
Jiří Rathouský ◽  
Arnošt Zukal
Keyword(s):  
Mesoporous Silica ◽  
Ethylene Oxide ◽  
Sodium Metasilicate ◽  
Spherical Particles ◽  
Structure Directing Agent ◽  
Inorganic Species ◽  
Poly Ethylene Oxide ◽  
Acidic Conditions ◽  
Poly Ethylene ◽  
Hydrolysis Of

A new procedure has been developed, which is based on homogeneous precipitation of organized mesoporous silica from an aqueous solution of sodium metasilicate and a nonionic poly(ethylene oxide) surfactant serving as a structure-directing agent. The decrease in pH, which induces the polycondensation of silica, is achieved by hydrolysis of ethyl acetate. Owing to the complexation of Na+ cations by poly(ethylene oxide) segments, assembling of the mesostructure appears to occur under electrostatic control by the S0Na+I- pathway, where S0 and I- are surfactant and inorganic species, respectively. As the complexation of Na+ cations causes extended conformation of poly(ethylene oxide) segments, the pore size and pore volume of organized mesoporous silica increase in comparison with materials prepared under neutral or acidic conditions. The assembling of particles can be fully separated from their solidification, which results in the formation of highly regular spherical particles of mesoporous silica.

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