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Drs. Wei Tian & Yanhui Chen Sep-Dec. 2014. Microscopic technique Scanning Electron Microscope (SEM) Transmission Electron Microscope (TEM) Atomic Force.

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Presentation on theme: "Drs. Wei Tian & Yanhui Chen Sep-Dec. 2014. Microscopic technique Scanning Electron Microscope (SEM) Transmission Electron Microscope (TEM) Atomic Force."— Presentation transcript:

1 Drs. Wei Tian & Yanhui Chen Sep-Dec. 2014

2 Microscopic technique Scanning Electron Microscope (SEM) Transmission Electron Microscope (TEM) Atomic Force Microscope (AFM)

3

4 Advantages  Simple preparation  Long depth of field  Wide view  High amplification factor  High resolution  Small damage  Comprehensive Analysis  Rapid data acquisition Limitations  Solid samples  Coating (Au, Au-Pd, etc.)  Vacuum environment

5 Application Application 1)Surface morphology 2)Crystal structure 3)Multi-phase structure 4)Acquiring elemental maps or spot chemical analyses using EDS (Energy-Dispersive X-Ray Spectroscopy) 5)Obtaining discrimination of phases based on mean atomic number (commonly related to relative density) using BSE (Back-scattered Electron Detector) 6)Getting compositional maps based on differences in trace element "activators" (typically transition metal and rare earth elements) using CL (cathodoluminescence)

6 Description Description Stegelmeier, C.; Filiz, V., et al. Macromolecules 2014, 47, 5566.

7 Incident high-kV beam

8 Imaging methods  Contrast formation  Bright field  Diffraction contrast  Electron energy loss  Phase contrast  Diffraction Disadvantages  A relatively time consuming process with a low throughput of samples  Sample damage  The field of view is relatively small Sample preparation  Tissue sectioning  Sample staining  Mechanical milling  Chemical etching  Ion etching  Replication

9 Polymer crystalline structure and morphology Application Distribution and size of micropores Polymer composition Distribution of dispersed phase lattice distortion

10 Examples Examples Graphene Carbon nanotube PE/SWNT NHSK

11 Pérez, R. A.; López, J. V., et al. Macromolecules 2014, 47, 3553. Description Description

12 Contact mode Tapping modeNon contact mode

13 Contact mode Non-contact Mode Tapping mode Limitations Easily damage soft samples due to the adhesive force Low lateral resolution Low scanning rate Only for water- funk samples Low lateral force Low scanning rate compared to contact mode Advantages Fast scanning rate Atomic resolution image Stiff samples with Vertical changes No force is applied on the samples High resolution No damage to the samples

14 Surface topography and microphase separation Identification of individual surface atoms Polymerization process Physical properties Application Application

15 Description Description Stegelmeier, C.; Filiz, V., et al. Macromolecules 2014, 47, 5566.

16 References 1. 田 威,孔 杰,胡思海. 高聚物的现代研究方法 [M] ,西北工 业大学出版社, 2014. 2.http://en.wikipedia.org/wiki/Scanning_electron_microscope 3.http://en.wikipedia.org/wiki/Transmission_electron_microscopy 4.http://en.wikipedia.org/wiki/Atomic_force_microscopy


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