Polyelectrolyte Functionalisation of Track Etched Membranes: Towards Charge-Tuneable Adsorber Materials

Abstract

Porous adsorber membranes are promising materials for the removal of charged pollutants, such as heavy metal ions or organic dyes as model substances for pharmaceuticals from water. Here, we present the surface grafting of polyethylene terephthalate (PET) track-etched membranes having well defined cylindrical pores of 0.2 or 1 µm diameter with two polyelectrolytes, poly(2-acrylamido glycolic acid) (PAGA) and poly(N-acetyl dehydroalanine) (PNADha). The polyelectrolyte functionalised membranes were characterised by changes in wettability and hydraulic permeability in response to the external stimuli pH and the presence of Cu2+ ions. The response of the membranes proved to be consistent with functionalisation inside the pores, and the change of grafted polyelectrolyte macro-conformation was due to the reversible protonation or binding of Cu2+ ions. Moreover, the adsorption of the model dye methylene blue was studied and quantified. PAGA-grafted membranes showed an adsorption behavior following the Langmuir model for methylene blue.

Protected Poly(3-sulfopropyl methacrylate) Copolymers: Synthesis, Stability, and Orthogonal Deprotection

“…Thus, PPhSPMA was successfully converted into the sodium salt of PSPMA. Similarly, the PBSPMA block of both PiBu-b-PPh and PiBu-b-PNeo was deprotected by using NaI: protons [1], [2], and [3] vanished, and the same shift of protons [*] could be recognized due to the changed chemical environment (Figure 3b,c).…”

“…Polyelectrolytes are macromolecules that carry ionic groups in their repeating unit, which renders them soluble in water and a limited number of polar organic solvents . Typical applications of these charged polymeric materials include their use in ultrafiltration membranes, , stabilizing agents, − underwater adhesives, − hydrogels, antifouling coatings, − and food packaging . Enhanced properties can often be achieved when the polymer of interest is combined with an oppositely charged species or a hydrophobic component, thereby resulting in a polyelectrolyte complex , or an amphiphilic copolymer, respectively.…”