Does Crystal Density Control Fast Surface Crystal Growth in Glasses? A Study with Polymorphs

2011 ◽  
Vol 11 (9) ◽  
pp. 3979-3984 ◽  
Author(s):  
Erica M. Gunn ◽  
Ilia A. Guzei ◽  
Lian Yu
Keyword(s):  
Crystal Growth ◽  
Density Control ◽  
Crystal Density ◽  
Surface Crystal

scholarly journals Crystal growth of the core and rotated epitaxial shell of a heterometallic metal-organic framework revealed with atomic force microscopy

2021 ◽  
Author(s):  
Fajar Inggit Pambudi ◽  
Michael William Anderson ◽  
Martin Attfield
Keyword(s):  
Atomic Force Microscopy ◽  
Crystal Growth ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Force Microscopy ◽  
The Core ◽  
Atomic Force ◽  
Metal Organic ◽  
Surface Crystal ◽  
Organic Framework

Atomic force microscopy has been used to determine the surface crystal growth of two isostructural metal-organic frameworks, [Zn2(ndc)2(dabco)] (ndc = 1,4-naphthalene dicarboxylate, dabco = 4-diazabicyclo[2.2.2]octane) (1) and [Cu2(ndc)2(dabco)] (2) from...

Bubble-induced fast crystal growth of indomethacin polymorphs in a supercooled liquid

2021 ◽  
Vol 54 (5) ◽  
Author(s):  
Qin Shi ◽  
Fang Li ◽  
Jia Xu ◽  
Lingling Wu ◽  
Junbo Xin ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Physical Stability ◽  
Pharmaceutical Formulations ◽  
Supercooled Liquid ◽  
Pharmaceutical Solids ◽  
Liquid Bubble ◽  
Different Temperatures ◽  
Surface Crystal

Physical stability is one of the main challenges when developing robust amorphous pharmaceutical formulations. This article reports fast crystal growth behaviors of the γ and α forms of indomethacin (IMC) initiated by bubbles in the interior of a supercooled liquid. Bubble-induced crystal growth of γ-IMC exhibits approximately the same kinetics as its surface crystal growth, supporting the view that bubble-induced crystal growth is a surface-facilitated process. In contrast, the rates of bubble-induced crystal growth of α-IMC are much faster than those of its surface crystal growth. These results indicate that the bubble-induced crystal growth not only depends on the interface created by the bubble but also strongly correlates with the true cavitation of the bubble. Moreover, bubble-induced fast crystal growth of γ- and α-IMC can be terminated at different temperatures by cooling. These outcomes are meaningful for the in-depth understanding of physical stability and pre-formulation study of amorphous pharmaceutical solids showing surface-facilitated crystal growth.

A Simple Method for Estimating the Extent of Surface Crystal Development on Colored Cheddar Cheese

1986 ◽  
Vol 49 (6) ◽  
pp. 421-422 ◽  
Author(s):  
STEPHEN T. DYBING ◽  
STEVEN A. BRUDVIG ◽  
JAMES A. WIEGAND ◽  
EMIL A. HUANG
Keyword(s):  
Crystal Growth ◽  
Shelf Life ◽  
Environmental Conditions ◽  
Cheddar Cheese ◽  
Simple Method ◽  
Flat Surfaces ◽  
White Cheese ◽  
Shelf Life Studies ◽  
Non Destructive ◽  
Surface Crystal

A simple, non-destructive method for estimating the extent of crystal development as white specks on the surface of colored Cheddar cheese is described. This method involves photocopying the surface of the cheese with a photocopier set at an exposure calibrated to clearly show the crystals. The photocopies of the cheese surface are then compared to a series of photocopies showing designated increases in crystal growth. Crystal development was rated as follows: 0 = no crystals, 1= light, 2 = medium, 3 = heavy, and 4 = very heavy to encrusted crystal development. The method does not disrupt or destroy the environmental conditions existing in the cheese package, allowing extended shelf life studies to be done on the same piece of cheese. However, the photocopy technique may not work as well with white cheese or cheeses without flat surfaces.

Crystallization of Organic Glasses: How Does Liquid Flow Damage Surface Crystal Growth?

2016 ◽  
Vol 16 (5) ◽  
pp. 2931-2936 ◽  
Author(s):  
Daniele Musumeci ◽  
Mariko Hasebe ◽  
Lian Yu
Keyword(s):  
Crystal Growth ◽  
Liquid Flow ◽  
Organic Glasses ◽  
Surface Crystal

Density of RDX Crystals Grown During High Acceleration in an Ultracentrifuge

2005 ◽  
Vol 896 ◽  
Author(s):  
Mary Y. D. Lanzerotti ◽  
Richard Z. Squillace ◽  
Alexander Gandzelko ◽  
Jagadish Sharma
Keyword(s):  
Crystal Growth ◽  
Maximum Density ◽  
Crystal Defects ◽  
Commercial Grade ◽  
Theoretical Maximum ◽  
High Acceleration ◽  
Cyclotrimethylene Trinitramine ◽  
Crystal Density ◽  
Defect Content ◽  
Solvent Molecules

AbstractRDX (cyclotrimethylene-trinitramine) crystals were grown during high acceleration (high g) in an ultracentrifuge. These crystals are found to have a density ∼0.6% greater than 1 g crystals and to have a greatly reduced defect content. The high g crystals should therefore have significantly reduced shock sensitivity as compared to commercial grade RDX. When a RDX saturated acetone solution is accelerated at 200,000 g, the RDX solute molecules move individually through the acetone solvent molecules to form a RDX crystal because the density of the RDX (Theoretical Maximum Density 1.806 g/cc) solute is more dense than the acetone (0.79 g/cc)solvent. Crystal growth is controlled by the g-force. Crystal defects including voids and solution inclusions caused by temperature variation or evaporation at 1 g are minimized and the RDX crystal density increases. A nitrogen pycnometer was used to measure the density of the RDX crystals grown at 1 g and at 200,000 g. The density of the RDX crystals grown at 200,000 g (1.7980±0.0003 g/cc) is found to be greater than the density of RDX crystals grown at 1 g (1.7881±0.0003 g/cc) by 0.0099 g/cc. The density of the high g crystal is 99.6% of the Theoretical Maximum Density of RDX.

Guided-mode refraction model for optical fiber sensing of surface crystal growth

2010 ◽  
Vol 35 (21) ◽  
pp. 3625 ◽  
Author(s):  
David W. Lamb ◽  
Martijn Boerkamp ◽  
Peter G. Lye
Keyword(s):  
Crystal Growth ◽  
Optical Fiber ◽  
Fiber Sensing ◽  
Guided Mode ◽  
Optical Fiber Sensing ◽  
Surface Crystal

Fast Surface Crystal Growth on Molecular Glasses and Its Termination by the Onset of Fluidity

2014 ◽  
Vol 118 (27) ◽  
pp. 7638-7646 ◽  
Author(s):  
Mariko Hasebe ◽  
Daniele Musumeci ◽  
C. Travis Powell ◽  
Ting Cai ◽  
Erica Gunn ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Molecular Glasses ◽  
Surface Crystal
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