Enhanced Antifouling Properties of Carbohydrate Coated Poly(ether sulfone) Membranes

Abstract

Polyethersulfone membranes (PES) were modified with biologically active monosaccharides and disaccharides using aryldiazonium chemistry as a mild, one step, surface modification strategy. We previously proposed the modification of carbon, metals, and alloys with monosaccharides using the same method; herein we demonstrate modification of PES membranes and the effect of chemisorbed carbohydrate layers on their resistance to biofouling. Glycosylated PES surfaces were characterized using spectroscopic methods and tested against their ability to interact with specific carbohydratebinding proteins. Galactose, mannose and lactose modified PES surfaces were exposed to Bovine Serum Albumin (BSA) solutions to assess unspecific protein adsorption in the laboratory and were found to adsorb significantly lower amounts of BSA compared to bare membranes. The ability of molecular carbohydrate layers to impart antifouling properties was further tested in the field via long term immersive tests at a wastewater treatment plant. A combination of ATP content assays, infrared spectroscopic characterization and He-ion microscopy (HIM) imaging were used to investigate biomass accumulation at membranes. We show that, beyond laboratory applications and in the case of complex aqueous environments that are rich in biomass such as wastewater effluent, we observe significantly lower biofouling at carbohydrate modified PES than at bare PES membrane surfaces.

Bioinspired Aryldiazonium Carbohydrate Coatings: Reduced Adhesion of Foulants at Polymer and Stainless Steel Surfaces in a Marine Environment

“…Coupons of polyethersulfone (PES), stainless steel (SS316) and Nylon-6 (N6) were first modified using lactoside groups via spontaneous reaction of aryldiazonium cations to yield Work from our group demonstrated that PES undergoes functionalization by spontaneous reaction after immersion of pristine substrates in these solutions and we refer to our previous publication for a full characterization of Lac-PES surfaces thus obtained. 33 In the case of SS316 and N6, surfaces were pre-activated prior to functionalization. SS316 surfaces were pre-activated in caustic hypochlorite (bleach) solutions; this treatment is known to have cleaning and oxidising effects on SS316 surfaces.…”

“…Carbohydrate layers prepared via aryldiazonium chemistry are molecular coatings in the 1-2 nm thickness range that preserve the topography of the original substrate, 31,33 so that their main effect is expected to be on surface chemistry and free energy. Results from field experiments show that in the absence of rinsing these coatings do not significantly impact on fouling resistance and little difference is observed with controls.…”

“…Results from field tests indicate that carbohydrate coatings show promise as a sustainable and environmentally benign approach for reducing adhesion and retention of marine foulants. Surface modification: Prior to modification with aryldiazonium cations, both polyamide and stainless steel surfaces were pre-activated, while PES surfaces did not require preactivation 33 and were used after light cleaning in methanol only. Nylon-6 (N6) samples were pre-activated by overnight immersion at 30 °C in a 36% aqueous formaldehyde solution with a catalytic amount of hypophosphorous acid.…”

Modulation of Protein Fouling and Interfacial Properties at Carbon Surfaces via Immobilization of Glycans Using Aryldiazonium Chemistry

“…In an effort to mimic biological antifouling strategies, work has focused on the use of immobilized carbohydrates, given the presence of these molecules in the antiadhesive glycocalyx that surrounds certain cells 18 19 . Research shows, in fact, that oligo- and polysaccharide coatings can control fouling and protein adsorption, while being extremely stable to oxidation 20 21 22 23 24 25 26 .…”

Microcapsules-based multifunctional coatings for anticorrosion and antibacterial applications

“…These coatings are environmentally benign and highly stable as compared to other chemical species. Additionally, these carbohydrate coatings were fabricated on poly (ether sulfone) (PES), which demonstrates lower fouling in a complex aqueous environments that are rich in biomass such as the wastewater effluent, as compared to the bare PES membrane surfaces [92]. Subsequently, the performance of carbohydrates immobilized fouling resistant coatings in the marine environment were studied on three different substrates: stainless steel, nylon and PES.…”