An optical chemical sensor based on polymer swelling and shrinking using dithiocarbamate-polymer microspheres

الملخص EN

In this work, an optical chemical sensor based on a swelling and shrinking polymer has been developed.

A dithiocarbamate functional group was attached chemically to the backbone of poly vinyl benzyl chloride which was lightly cross-linked with divinely benzene.

The derivative polymer microspheres were dispersed in a hydrogel membrane to produce a sensing element.

This modified membrane was used for sensing specific heavy metal ions, such as Hg2+.

The response is based on the interaction between the metal actions with the negative charges of the deprotonated dithiocarbamate functional group, whereby the swell able polymer undergoes shrinking as a result of neutralization of the negative charges of this functional group.

This complex formation of a metal action with a dithiocarbamate functionality causes significant changes in the optical properties of the sensing element.

Shrinking of the polymer microspheres resulted in a decrease in the optical transmission through the sensing membrane.

This is due to the increasing difference in refractive indices between the microspheres and the dispersing hydrogel membrane.

This sensor showed a good response particularly to mercury ion.

There was insignificant response to H+ in the pH range 2-13.

In addition, there was no detectable response towards alkali, alkaline earth metals and other heavy metal ions such as Pb2+, Zn2+, and Cd2+.