Tunable Organogelator from Alkyl-Polypeptide Diblock Prepared by Ring-Opening Polymerization

2014 ◽  
Vol 67 (1) ◽  
pp. 59 ◽  
Author(s):  
Chongyi Chen ◽  
Decheng Wu ◽  
Wenxin Fu ◽  
Zhibo Li
Keyword(s):  
Atomic Force Microscopy ◽  
Organic Solvents ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Low Concentration ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Circular Dichroïsm ◽  
Β Sheet

Three alkyl-polypeptide hybrid amphiphiles were synthesized by the ring-opening polymerization (ROP) of γ-(2-methoxyethoxy)esteryl-l-glutamate N-carboxyanhydride (l-EG1Glu NCA) using alkylamine, i.e. C6H13NH2, C14H29NH2, and C16H33NH2, as initiators. As-prepared alkyl-poly-l-EG1Glu hybrids were found to form clear organogels in several organic solvents at low concentration. FTIR and circular dichroism characterizations suggested that poly-l-EG1Glu formed a predominantly β-sheet conformation, which accounted for the gelation. Transmission electron and atomic force microscopy characterizations revealed that these copolymers formed nanoribbon structures in THF.

Defect-Engineered Graded GexSi1-x Buffers on Si (001) with Extreme Low Threading Dislocation Density

1995 ◽  
Vol 378 ◽  
Author(s):  
G. Kissinger ◽  
T. Morgenstern ◽  
G. Morgenstern ◽  
H. B. Erzgräber ◽  
H. Richter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Dislocation Density ◽  
Threading Dislocation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Threading Dislocation Density

AbstractStepwise equilibrated graded GexSii-x (x≤0.2) buffers with threading dislocation densities between 102 and 103 cm−2 on the whole area of 4 inch silicon wafers were grown and studied by transmission electron microscopy, defect etching, atomic force microscopy and photoluminescence spectroscopy.

The structure of hydrous flocs prepared by batch and continuous flow water treatment systems and obtained by optical, electron and atomic force microscopy

1997 ◽  
Vol 36 (4) ◽  
pp. 41-48 ◽  
Author(s):  
A. Cornelissen ◽  
M. G. Burnett ◽  
R. D. McCall ◽  
D. T. Goddard
Keyword(s):  
Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Continuous Flow ◽  
Structural Information ◽  
Preparation Technique ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Optical Electron ◽  
Artefact Formation

This paper concerns the imaging of hydrous floc particles by Light Microscopy (LM), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM). The use of a microscope technique means that visual structural information is obtained, in contrast with other techniques measuring particle characteristics. It was found that when a preparation technique was used that involves cryogenic freezing of the sample, before observation in the SEM, larger (1-100 μm) floc particles could be imaged without the loss of structural information normally caused by drying the sample. Damage caused by drying was not apparent with the TEM technique used. It was shown that the various microscope techniques produced compatible results, together covering a wide size range (10 nm-5mm). This indicates that major artefact formation due to sample preparation is unlikely. It was furthermore shown that when a micro-scale continuous flow system was used the reproducibility of the floc structure observed increased.

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