Insight into carbon nanotube effect on polymer molecular orientation: an infrared dichroism study

2011 ◽  
Vol 47 (3) ◽  
pp. 899-901 ◽  
Author(s):  
Cuiping Yuan ◽  
Jinhao Zhang ◽  
Guangming Chen ◽  
Jiping Yang
2016 ◽  
Vol 2 (10) ◽  
pp. e1601006 ◽  
Author(s):  
Eric A. Muller ◽  
Benjamin Pollard ◽  
Hans A. Bechtel ◽  
Peter van Blerkom ◽  
Markus B. Raschke

Molecular solids and polymers can form low-symmetry crystal structures that exhibit anisotropic electron and ion mobility in engineered devices or biological systems. The distribution of molecular orientation and disorder then controls the macroscopic material response, yet it is difficult to image with conventional techniques on the nanoscale. We demonstrated a new form of optical nanocrystallography that combines scattering-type scanning near-field optical microscopy with both optical antenna and tip-selective infrared vibrational spectroscopy. From the symmetry-selective probing of molecular bond orientation with nanometer spatial resolution, we determined crystalline phases and orientation in aggregates and films of the organic electronic material perylenetetracarboxylic dianhydride. Mapping disorder within and between individual nanoscale domains, the correlative hybrid imaging of nanoscale heterogeneity provides insight into defect formation and propagation during growth in functional molecular solids.


2018 ◽  
Vol 122 (41) ◽  
pp. 23385-23392 ◽  
Author(s):  
Shubhadeep Pal ◽  
Sreekanth Narayanaru ◽  
Biswajit Kundu ◽  
Mihir Sahoo ◽  
Sumit Bawari ◽  
...  

2018 ◽  
Vol 25 (5) ◽  
pp. 891-901 ◽  
Author(s):  
Lijun Wang ◽  
Jianhui Qiu ◽  
Eiichi Sakai

AbstractIn this work, the rolling process was employed to fabricate polylactic acid/multi-walled carbon nanotube (PLA/MWCNT) composites at room temperature. The effects of the rolling conditions on the mechanical and electrical properties of the fabricated composites were investigated. The evolution processes of the internal molecular structures, i.e. changes in molecular orientation and crystallinity, were examined by X-ray diffraction, differential scanning calorimetry, and density method. The results suggested that the molecular orientation improved; however, the crystallinity decreased when the rolling ratio increased. The analysis of the mechanical properties revealed that the rolled composites displayed anisotropy during the rolling process. In the rolling direction, after adding 1 wt.% MWCNTs, the tensile strength increased from 58.6 to 94.3 MPa with the rolling ratio, whereas the fracture strain sharply increased to 131.5% at the rolling ratio of 60%. In addition to the mechanical properties, electrical resistivity was also investigated; notably, this property was not significantly affected by the rolling process. Furthermore, the MWCNT dispersion and morphology were investigated by scanning electron microscopy. These findings offer a simple and effective method to fabricate conductive composites with excellent mechanical properties.


2016 ◽  
Vol 30 (06) ◽  
pp. 1650019 ◽  
Author(s):  
Xianwen Meng ◽  
Jiping Huang

We utilize molecular dynamics simulations to study the effect of an electric field on the permeation of water molecules through a defective single-walled carbon nanotube (DSWCNT). Compared with a perfect single-walled carbon nanotube (PSWCNT), the behaviors of water molecules respond more quickly under the same electric field in a DSWCNT. Wet–dry phase transition of water molecules occurs when the electric field reaches 0.32 V/nm, which is much lower than the case of the PSWCNT. Besides, the critical electric field is affected by the number of defects. These results pave a way for designing fast wet–dry transition devices and provide a new insight into water permeation through a defective nanochannel.


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