Ion-dipole interactions and chiroptical property changes of an optically active nylon-type polyamide in CaCl2
-methanol solutions

l -Cysteine is one of the most promising biomass-based building blocks with great potential applications. Herein, we report a versatile synthetic route to produce cysteine-based 2,5-diketopiperazine (DKP) with good yield from the thiol-ene click reaction of l -cysteine and commercially available acrylates, followed by dimerization of the amino acid intermediates. The achieved DKP diastereomers were successfully separated and fully characterized by spectroscopic methods. Moreover, the chiroptical property of DKP in the presence of various metal ions was investigated by circular dichroism spectroscopy. The potential application of the optically active cysteine-based DKP as a chiral probe for detection of silver ion in water has been demonstrated.

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Dielectric properties of dielectrophoretically assembled particulate-polymer composites

Journal of Materials Research ◽

10.1557/jmr.1998.0027 ◽

1998 ◽

Vol 13 (1) ◽

pp. 205-210 ◽

Cited By ~ 59

Author(s):

C. P. Bowen ◽

R. E. Newnham ◽

C. A. Randall

Keyword(s):

Dielectric Properties ◽

Electric Field ◽

Electric Fields ◽

Dipole Interaction ◽

Filler Materials ◽

Polymer Phase ◽

Dipole Interactions ◽

Assembly Technique ◽

Composite Microstructure ◽

Property Changes

The dielectrophoretic effect is a phenomenon in which dipole-dipole interactions are induced between particles in a suspension by an electric field.1−5 This dipole interaction leads to the formation of chains or fibrils parallel to the applied electric field. Recently, the dielectrophoretic effect has been shown to be a possible composite assembly technique permitting property changes to be induced with the appropriate electric fields.6,7 The results presented in this paper show that the dielectrophoretic assembly process can be used to engineer anisotropy into composite materials. Various filler materials are aligned in a thermoset polyurethane matrix and the dielectric properties are measured. Comparisons are drawn between the dielectrophoretically assembled composites and those processed conventionally in the absence of an electric field. Dielectric properties are modeled with modified mixing laws and discussed in relation to the composite microstructure and the alpha relaxations of the polymer phase.

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Analytical Electron Microscopy of Ion-Implanted Metals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010011831x ◽

1985 ◽

Vol 43 ◽

pp. 282-285

Author(s):

D.I. Potter ◽

M. Ahmed ◽

K. Ruffing

Keyword(s):

Electron Microscopy ◽

Ion Implantation ◽

Friction And Wear ◽

Analytical Electron Microscopy ◽

Chemical Compositions ◽

Surface Chemical ◽

Near Surface ◽

The Past ◽

Analytical Electron ◽

Property Changes

Ion implantation, used extensively for the past decade in fabricating semiconductor devices, now provides a unique means for altering the near-surface chemical compositions and microstructures of metals. These alterations often significantly improve physical properties that depend on the surface of the material; for example, catalysis, corrosion, oxidation, hardness, friction and wear. Frequently the mechanisms causing these beneficial alterations and property changes remain obscure and much of the current research in the area of ion implantation metallurgy is aimed at identifying such mechanisms. Investigators thus confront two immediate questions: To what extent is the chemical composition changed by implantation? What is the resulting microstructure? These two questions can be investigated very fruitfully with analytical electron microscopy (AEM), as described below.

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Relationships Between Grain Boundary Structure and Material Properties

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600001550 ◽

1980 ◽

Vol 38 ◽

pp. 366-369

Author(s):

Brian Ralph ◽

Barlow Claire ◽

Nicola Ecob

Keyword(s):

Grain Boundary ◽

Material Properties ◽

Main Property ◽

Grain Structure ◽

Boundary Structure ◽

Grain Boundary Structure ◽

Property Changes

This brief review seeks to summarize some of the main property changes which may be induced by altering the grain structure of materials. Where appropriate an interpretation is given of these changes in terms of current theories of grain boundary structure, and some examples from current studies are presented at the end of this paper.

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