Modifying the Selectivity of Zwitterionic Copolymer Membranes by Molecular Imprinting
Lind, William.
2016
-
Abstract: Membranes
are widely used to perform solution separations based on the size of solutes, but there
are many applications where more complex basis of separation is needed. Molecular
imprinting involves manufacturing a polymeric material (e.g. membrane or adsorbent) in
the presence of a target solute that is later removed. This creates binding pockets that
enhance the interaction of ... read morethat solute with the polymer during operation, and can change
the adsorption and permeation selectivity of the polymeric material. In this work, we
utilize a molecular imprinting approach to combine the size-based separation
capabilities of thin film composite membranes made from a zwitterion-containing
amphiphilic copolymer with structure-specific separation capabilities. In so doing, we
create a membrane that can distinguish between solutes based on size, but whose
preference for selected solutes can be enhanced by simply altering the membrane
manufacturing procedure. To achieve this, we prepared thin film composite membranes
whose selective layers are formed by coating a thin selective layer of a zwitterionic
copolymer blended with an imprinting molecule. We then characterized the performance of
the membrane through filtration experiments. We saw that when a zwitterionic solute such
as Vitamin B12 was used as the additive during manufacture, the permeation of that
solute and other zwitterionic solutes was enhanced but that of other solutes (e.g.
anionic dyes) was not affected. Interestingly, a similar effect was not observed when an
anionic solute, Direct Red 80, was used for the imprinting step. This did not lead to
any significant changes in membrane selectivity. Thus, based on our results to date, the
molecular imprinting effect is specific to zwitterion imprinting agents and solutes and
is strongest when the imprinting agent is identical to the solute. Future work can
better clarify what inter-molecular interactions lead to these results, and if the
observed effect is general to all zwitterionic
solutes.
At the request of the author, this graduate work is not available to view in the Tufts Digital Library.
Thesis (M.S.)--Tufts University, 2016.
Submitted to the Dept. of Chemical and Biological Engineering.
Advisor: Ayse Asatekin.
Committee: Matthew Panzer, and Peggy Cebe.
Keywords: Chemical engineering, Polymer chemistry, and Materials Science.read less - ID:
- 37720r08b
- Component ID:
- tufts:21245
- To Cite:
- TARC Citation Guide EndNote
