Depth Dependence of the Surface Glass Transition Temperature of a Poly(styrene-block-methyl methacrylate) Diblock Copolymer Film on the Basis of Temperature-Dependent X-ray Photoelectron Spectroscopy

1995 ◽  
Vol 28 (9) ◽  
pp. 3482-3484 ◽  
Author(s):  
Tisato Kajiyama ◽  
Keiji Tanaka ◽  
Atsushi Takahara
2019 ◽  
Author(s):  
Anna J Warren ◽  
Danny Axford ◽  
Robin L Owen

AbstractTemperature control is a key aspect of macromolecular crystallography, with the technique of cryocooling routinely used to mitigate X-ray induced damage. Beam induced heating could cause the temperature of crystals to rise above the glass transition temperature, greatly increasing the rate of damage. X-ray induced heating of ruby crystals 20-40 microns in size has been quantified non-invasively by monitoring the emission wavelengths of X-ray induced fluorescence during exposure to the X-ray beam. For beamsizes and dose-rates typically used in macromolecular crystallography the temperature rises are of order 20 K. The temperature changes observed are compared with models in the literature and can be used as a validation tool for future models.SynopsisX-ray induced heating of micro-crystals is quantified through the temperature-dependent shift in X-ray induced fluorescence from ruby crystals.


2018 ◽  
Vol 46 (3) ◽  
pp. 117-121 ◽  
Author(s):  
Asae Ito ◽  
Viknasvarri Ayerdurai ◽  
Azusa Miyagawa ◽  
Akikazu Matsumoto ◽  
Haruki Okada ◽  
...  

2000 ◽  
Vol 629 ◽  
Author(s):  
Y. Grohens ◽  
L. Hamon ◽  
P. Carriere ◽  
Y. Holl ◽  
J. Schultz

ABSTRACTThe glass transition temperature (Tg) of thin supported films of stereoregular poly(methyl methacrylate) on silicon has been investigated by ellipsometry in temperature. The Tg of the spin coated layers of isotactic PMMA increases for thickness lower than 100 nm whereas a depression of the Tg is observed for the syndiotactic PMMA. This opposite trend in the Tg variation in thin layer between the two isomers evidenced a fascinating effect of the chain organization at an interacting interface. Hydrofluric acid surface etching of the silicon wafer was shown to decrease the threshold thickness at which the change in Tg occurs for both PMMA isomers. The influence of the interfacial interactions along with the tacticity dependent characteristics of the polymer will be discussed.


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