Study of the Crystal Growth Mechanism and Critical Secondary Nucleus Size of Poly(ethylene oxide)/Urea Inclusion Compound

2019 ◽  
Vol 19 (7) ◽  
pp. 3834-3842 ◽  
Author(s):  
Yang Gao ◽  
Shujing Zhang ◽  
Jiaxin Shi ◽  
Baohua Guo ◽  
Jun Xu
Keyword(s):  
Crystal Growth ◽  
Ethylene Oxide ◽  
Inclusion Compound ◽  
Nucleus Size ◽  
Secondary Nucleus ◽  
Crystal Growth Mechanism ◽  
Urea Inclusion Compound ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Urea Inclusion

scholarly journals Critical Size of Secondary Nuclei Determined via Nucleation Theorem Reveals Selective Nucleation in Three-Component Co-Crystals

Entropy ◽  
2019 ◽  
Vol 21 (11) ◽  
pp. 1032 ◽  
Author(s):  
Yang Gao ◽  
Baohua Guo ◽  
Jun Xu
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Ethylene Oxide ◽  
Inclusion Compound ◽  
Critical Size ◽  
Lateral Spreading ◽  
Crystal Growth Rate ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Nucleation Theorem

The critical size of the secondary nuclei plays an important role in determining the crystal growth rate. In the past, the Nucleation Theorem has been applied to determine the number of molecules in the critical nuclei of a single-component crystal via variation of the crystal growth rate with dilution by the non-crystallizable component. In this work, we extend the method to the three-component co-crystal poly (ethylene oxide)/urea/thiourea inclusion compound. The theoretical crystal growth kinetics were deduced and the dependence of the radial growth rate of the inclusion compound spherulites on the mass fraction of urea in urea/thiourea was measured. The results reveal that the secondary nuclei of the poly (ethylene oxide)/urea/thiourea inclusion compound consist mainly of ethylene oxide repeating units and urea molecules. We propose that only urea molecules and ethylene oxide repeating units are selected to form the secondary nuclei while co-crystallization of the three components happens at the lateral spreading stage. As a result, the composition of the critical secondary nuclei is different from that of the bulk inclusion compound crystals. The work is expected to deepen our understanding of the nucleation of multi-component co-crystals.

Crystal Growth Mechanism Changes in Pseudo-Dewetted Poly(ethylene oxide) Thin Layers

2007 ◽  
Vol 40 (5) ◽  
pp. 1570-1578 ◽  
Author(s):  
Dun-Shen Zhu ◽  
Yi-Xin Liu ◽  
Er-Qiang Chen ◽  
Ming Li ◽  
Chao Chen ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Ethylene Oxide ◽  
Growth Mechanism ◽  
Thin Layers ◽  
Crystal Growth Mechanism ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

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.

Crystal growth of intermediate-molecular-mass poly(ethylene oxide) fractions from the melt

Polymer ◽  
1990 ◽  
Vol 31 (6) ◽  
pp. 1018-1024 ◽  
Author(s):  
Stephen Z.D. Cheng ◽  
Jianhua Chen ◽  
James J. Janimak
Keyword(s):  
Crystal Growth ◽  
Ethylene Oxide ◽  
Molecular Mass ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

Orientation of polymer chains in spherulites of poly(ethylene oxide)-urea inclusion compounds

Polymer ◽  
2017 ◽  
Vol 130 ◽  
pp. 209-217 ◽  
Author(s):  
Yang Gao ◽  
Shu-Fang Yao ◽  
Hai-Mu Ye ◽  
Bao-Hua Guo ◽  
Jun Xu
Keyword(s):  
Ethylene Oxide ◽  
Inclusion Compounds ◽  
Polymer Chains ◽  
Urea Inclusion Compounds ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Urea Inclusion
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