Yau Shan Szeto

Suspension of Silver Oxide Nanoparticles in Chitosan Solution and its Antibacterial Activity in Cotton Fabrics

New stable silver oxide suspension in chitosan solution was prepared from a mixture of silver nitrate and chitosan in dilute acetic acid as precursor, in which the complex interactions between silver ion and chitosan was also investigated through various instrumentation method seriously. The suspension was charactized through laser scan, infrared ray spectroscopy (IR), ultraviolet-visible spectroscopy (UV-vis) and X-ray diffraction (XRD), which indicated that the interactions between silver and chitosan in its precursor were destroyed partially. The measurements of the nanoparticles through scanning electron microscopy (SEM) and transmission electron microscopy (TEM) disclosed the spherical profiles of these silver oxide nanoparticles of 10-20nm in average. Cotton fabrics treated by this emulsion were entitled remarkable antibacterial activity against S aureus and E. coli at pH 5 and 7 with sightless color effect and good washing fastness.

Carboxamidophenylsydnone : a mesoionic mesogen for liquid crystals

Abstract A new class of liquid crystals based on carboxamidophenylsydnone was synthesized by a simple reaction between 3-(4-aminophenyl)sydnone and appropriate aliphatic carboxylic acids in the presence of SiCl 4 .

An convenient method for the synthesis of 7,8-dimethoxy-3-hydroxyquinolin-2(1H-one and its tautomer conformation study

3-Hydroxyquinolin-2(1H)-one (1) was synthesized successfully from readily available 2-nitroveratraldehyde in a three-step reaction. The procedure was based on existing protocol but with slight modification to give a much higher production yield. The tautomer conformation of the quinolinone was studied.