Degradation and stability of polyaniline on exposure to electron beam irradiation (structure–property relationship)

2007 ◽  
Vol 92 (10) ◽  
pp. 1824-1832 ◽  
Author(s):  
Sambhu Bhadra ◽  
Dipak Khastgir
2016 ◽  
Vol 89 (3) ◽  
pp. 477-498 ◽  
Author(s):  
Padmanabhan Ramachandran ◽  
Kinsuk Naskar ◽  
Golok B. Nando

ABSTRACT The effects of electron beam irradiation on the structure–property relationship of blends can be studied based on ethylene octene copolymer (EOC) and polydimethyl siloxane (PDMS) rubber at three different blend ratios prepared with a melt mixing technique. Irradiation with 2.5 MeV electron beam accelerating energy, over a radiation dose varying from 25 to 150 kGy, causes cross-linking in both the EOC and the PDMS phases. However, cross-linking of the EOC phase without affecting the crystallinity of the EOC polymer leads to tremendous improvement in the physicomechanical properties, including the tensile strength, which improves by nearly 35% for 70:30 EOC:PDMS blends. Morphology of the blends before and after irradiation can be analyzed by scanning electron microscopy and atomic force microscopy and correlated with the physicomechanical properties. The physicomechanical properties of the individual polymer components after irradiation show that radiation cross-linking is more effective for PDMS rubber than it is for EOC. However, at higher radiation doses, chain scissions are possible in both EOC and PDMS rubber, which affect the physicomechanical properties. Through blending and subsequent radiation cross-linking, the maximum degradation temperature of EOC can be increased from 488.6 to 512.8 °C.


Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Binbin Jin ◽  
Ding Zhao ◽  
Fei Liang ◽  
Lufang Liu ◽  
Dongli Liu ◽  
...  

Organic-inorganic hybrid perovskites (OIHPs) have been intensively studied due to their fascinating optoelectronic performance. Electron microscopy and related characterization techniques are powerful to figure out their structure-property relationships at the nanoscale. However, electron beam irradiation usually causes damage to these beam-sensitive materials and thus deteriorates the associated devices. Taking a widely used CH3NH3PbI3 film as an example, here, we carry out a comprehensive study on how electron beam irradiation affects its properties. Interestingly, our results reveal that photoluminescence (PL) intensity of the film can be significantly improved along with blue-shift of emission peak at a specific electron beam dose interval. This improvement stems from the reduction of trap density at the CH3NH3PbI3 surface. The knock-on effect helps expose a fresh surface assisted by the surface defect-induced lowering of displacement threshold energy. Meanwhile, the radiolysis process consistently degrades the crystal structure and weaken the PL emission with the increase of electron beam dose. Consequently, the final PL emission comes from a balance between knock-on and radiolysis effects. Taking advantage of the defect regulation, we successfully demonstrate a patterned CH3NH3PbI3 film with controllable PL emission and a photodetector with enhanced photocurrent. This work will trigger the application of electron beam irradiation as a powerful tool for perovskite materials processing in micro-LEDs and other optoelectronic applications.


Author(s):  
B. L. Armbruster ◽  
B. Kraus ◽  
M. Pan

One goal in electron microscopy of biological specimens is to improve the quality of data to equal the resolution capabilities of modem transmission electron microscopes. Radiation damage and beam- induced movement caused by charging of the sample, low image contrast at high resolution, and sensitivity to external vibration and drift in side entry specimen holders limit the effective resolution one can achieve. Several methods have been developed to address these limitations: cryomethods are widely employed to preserve and stabilize specimens against some of the adverse effects of the vacuum and electron beam irradiation, spot-scan imaging reduces charging and associated beam-induced movement, and energy-filtered imaging removes the “fog” caused by inelastic scattering of electrons which is particularly pronounced in thick specimens.Although most cryoholders can easily achieve a 3.4Å resolution specification, information perpendicular to the goniometer axis may be degraded due to vibration. Absolute drift after mechanical and thermal equilibration as well as drift after movement of a holder may cause loss of resolution in any direction.


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