Thermoreversible Polymer Gels in DMF Formed from Charge- and Crystallization-Induced Assembly.

Tao Zhang,Guangtao Chang,Qipeng Guo

doi:10.3390/polym12092056

Abstract

Polymer organogels formed through dynamic interactions are interesting for various applications. The fabrication of polymer organogels in polar solvents through ionic interaction is rare, although such organogels in non-polar organic solvents have been well studied. Herein, polymer organogels in a polar solvent N,N-dimethyl formamide (DMF) were fabricated from a triblock copolymer, poly(4-vinyl pyridine)-block-poly(ethylene glycol)-block-poly(4-vinyl pyridine) (4VPm-EGn-4VPm), and a fluorinated surfactant, perfluorooctanoic acid (PFOA), and their microphase separation and properties were studied. Ordered microphase separation and the crystalline structures were revealed by small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS), respectively. All the 4VPm-EGn-4VPm/PFOA organogels are sensitive to temperature, and the ratio of PFOA to pyridine groups reversibly. The polymer organogels are also responsive to triethylamine and triethylammonium acetate.

Highlights

Responsive organogels exhibit changes in their physicochemical properties in response to external triggers, and such organogels are of current interest in both the academic community and industrial field, due to their fascinating properties and widespread applications from oil technology to drug delivery [1,2,3,4].A promising class of responsive organogels is polymer networks crosslinked by physical interactions, since such dynamic interactions enable the networks to be reversible [5]
Polymer organogels have been stabilized by the formation of helical structures [6,7], π–π stacking [8], hydrogen bonding [9], addition of cross-linkers [10,11] and the assembly of block copolymer [12], more driving forces still need to be explored in order for them to satisfy various applications
The m n m solution in with an equimolar amount of groups and pyridine groups, and solution in dimethyl formamide (DMF) with an equimolar amount of –COOH groups and pyridine groups, and the formationthe of formation was of organogels wasbydemonstrated by the tube-inversion method [31]

Summary

Introduction

Responsive organogels exhibit changes in their physicochemical properties in response to external triggers, and such organogels are of current interest in both the academic community and industrial field, due to their fascinating properties and widespread applications from oil technology to drug delivery [1,2,3,4].A promising class of responsive organogels is polymer networks crosslinked by physical interactions, since such dynamic interactions enable the networks to be reversible [5]. Polymer organogels have been stabilized by the formation of helical structures [6,7], π–π stacking [8], hydrogen bonding [9], addition of cross-linkers [10,11] and the assembly of block copolymer [12], more driving forces still need to be explored in order for them to satisfy various applications. Ionic aggregates are required to form strong cross-linkers in water [28], while a single ionic bond is strong enough to stabilize three-dimensional networks without solvents [15]. There are few organogels in polar solvents stabilized by ionic interactions [20,29]

Methods

Results

Conclusion