4.5.4 Glycosylation by UV-Induced Polymerization
Glycosylation of the membrane surface was performed by UV-induced polymerization which results in increased membrane performance. The water flux depends
more on surface hydrophilicity than on pore properties as long as the degree of
grafting is low. Therefore, during grafting gas flux decreases while the water flux
increases (Xu et al. 2009). Antifouling property and hydrophilicity of polyacrylonitrile (PAN) ultrafiltration membrane was improved by grafting a ring-opening
glycomonomer d-gluconamidoethyl methacrylate (GAMA) onto the membrane
surface by ultraviolet (UV)-initiated grafting polymerization. This resulted in
increased flux recovery ratio, indicating that the antifouling of PAN membrane
was improved by the glycosylation (Dai et al. 2008).
4.5.5 Glycosylation by Polymer Analogous Reactions
Glycosylation by polymer analogous reaction is a two-step method for the modification of polymer membrane. In polymer analogous reaction, polymers with functional groups were grafted on to the membrane surface, and then the sugars were
immobilized on the surface by the reactions between sugar moieties and functional
groups. The grafted polymeric chains showed much higher hydrophilicity than in
nascent membranes (Xu et al. 2009). Using polymer analogous reaction, acrylamide
(AAm) was grafted on the membrane by UV-induced polymerization, and sugars
were immobilized by converting amide groups to amine groups by Hofmann
rearrangement reaction.
4.5.6 Glycosylation by Surface-Initiated Living
Polymerization
Conventional grafting techniques suffer with many disadvantages like lack of
control over molecular structure, incapable of further increasing the sugar density,
and also glycopolymer chain length may largely affect the recognition activity. In
order to overcome the above problems, glycopolymer with a well-defined chain
structure and appropriate sugar density was generated which resulted in glycosylated
membrane surface with controlled molecular weight and structures. The chain length
of the grafted glycopolymer can be controlled by adjusting the polymerization time
(Xu et al. 2009). Yang et al. prepared comb-like glycopolymer brushes by grafting
poly(2-hydroxyethyl methacrylate) (PHEMA) with hydroxyl groups to the polypropylene microporous membrane surface by UV-induced graft polymerization (Yang
et al. 2007).
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J. Ganesan et al.
Glycosylation of the membrane surface was performed by UV-induced polymerization which results in increased membrane performance. The water flux depends
more on surface hydrophilicity than on pore properties as long as the degree of
grafting is low. Therefore, during grafting gas flux decreases while the water flux
increases (Xu et al. 2009). Antifouling property and hydrophilicity of polyacrylonitrile (PAN) ultrafiltration membrane was improved by grafting a ring-opening
glycomonomer d-gluconamidoethyl methacrylate (GAMA) onto the membrane
surface by ultraviolet (UV)-initiated grafting polymerization. This resulted in
increased flux recovery ratio, indicating that the antifouling of PAN membrane
was improved by the glycosylation (Dai et al. 2008).
4.5.5 Glycosylation by Polymer Analogous Reactions
Glycosylation by polymer analogous reaction is a two-step method for the modification of polymer membrane. In polymer analogous reaction, polymers with functional groups were grafted on to the membrane surface, and then the sugars were
immobilized on the surface by the reactions between sugar moieties and functional
groups. The grafted polymeric chains showed much higher hydrophilicity than in
nascent membranes (Xu et al. 2009). Using polymer analogous reaction, acrylamide
(AAm) was grafted on the membrane by UV-induced polymerization, and sugars
were immobilized by converting amide groups to amine groups by Hofmann
rearrangement reaction.
4.5.6 Glycosylation by Surface-Initiated Living
Polymerization
Conventional grafting techniques suffer with many disadvantages like lack of
control over molecular structure, incapable of further increasing the sugar density,
and also glycopolymer chain length may largely affect the recognition activity. In
order to overcome the above problems, glycopolymer with a well-defined chain
structure and appropriate sugar density was generated which resulted in glycosylated
membrane surface with controlled molecular weight and structures. The chain length
of the grafted glycopolymer can be controlled by adjusting the polymerization time
(Xu et al. 2009). Yang et al. prepared comb-like glycopolymer brushes by grafting
poly(2-hydroxyethyl methacrylate) (PHEMA) with hydroxyl groups to the polypropylene microporous membrane surface by UV-induced graft polymerization (Yang
et al. 2007).
144
J. Ganesan et al.