Synthesis and characterization of zwitterionic organogels based on Schiff base chemistry

Abstract

Poly(sulfobetaine)s and poly(carboxybetaine)s have been extensively studied for their zwitterionic and biocompatible nature. The specific features that make such zwitterionic structures technologically important are their chemical structure, a straight forward synthetic route, high ionic contents with interesting dilute solution, and solid state properties. The objective of this work is to synthesize novel zwitterionic polymers having gel characteristics. Here, p-phenylene diamine/melamine react as nucleophiles with glutaraldehyde to produce poly(schiff base)s. In the subsequent step, the poly(sulfobetaine)s and poly(carboxybetaine)s were produced on treatment with 1,3-propane sultone/c-butyrolactone. Hence, a catalyst free facile approach to novel zwitterionic polymers was obtained. The polymers were characterized by elemental analyses, FTIR, XRD analyses, SEM, pH metric titrations, conductometric titrations, and thermal analyses (TGA/ DTA). The polymeric samples carry the gel characteristics, showing lamellar structure with porous network. XRD pattern shows Bragg peaks indicative of superstructures. Thermal analysis indicates the Hoffman elimination of b hydrogen and subsequent release of sulfopropyl/carboxybutyl group. One of the gel polymers shows fluorescence also.

Structures and Synthesis of Zwitterionic Polymers

“…Note that occasional claims about ring opening alkylation by -butyrolactone (Scheme 7, m = 3) [55,80] must be taken with great care, as they are most probably erroneous. In particular in the case of primary and secondary amines, the reaction of -butyrolactone will anyhow result in ring opening acylation to create amides instead of amines.…”

“…With a pK a < 1, the latter are operative as cationic group throughout the whole pH window of water ( Figure 1, motif X). Still, azomethines are highly sensitive to hydrolysis, in particular when protonated or quaternized, and such fragile structures have been reported only exceptionally as cationic groups for polyzwitterions [80]. Figure 1.…”

Synthesis and swelling characteristics of responsive carboxybetaine gel

“…Here, the aromatic group from the melamine facilitates the delocalization of the probable charge centers on the C atom of imine groups. 34 The resulting polyimine was treated with γ‐ butyrolactone followed by DEGDA as a crosslinker in varying ratio. The extent of gelation as well as the time period needed for gelation depends on the amount of crosslinker, as shown in Table I, signifying the major role of crosslinking chemistry in the formation of gel.…”

Synthesis of organic sulfobetaine‐based polymer gel electrolyte for dye‐sensitized solar cell application

“…Polybetaines are polymers possessing anionic and cationic groups on the same monomer unit. Polymers with zwitterionic skeleton are technologically important because of their high ionic content, chemical structure, thermal stability, and solid state properties . Polyimines are polymers with Schiff bases as unit and bearing good engineering properties and mechanical strength like favorable electronic/optoelectronic, liquid crystalline behavior, good thermal stability, and promising biological property .…”

“…Polymers with zwitterionic skeleton are technologically important because of their high ionic content, chemical structure, thermal stability, and solid state properties. [20] Polyimines are polymers with Schiff bases as unit and bearing good engineering properties and mechanical strength like favorable electronic/optoelectronic, liquid crystalline behavior, good thermal stability, and promising biological property. [21][22][23][24] In this report, we fabricated DSSC based on PAN/PS polyblend gel electrolyte instead of liquid electrolyte and compared the results.…”