Triblock Copolymer Self-Assembly in Ionic Liquids: Effect of PEO Block Length on the Self-Assembly of PEO–PPO–PEO in Ethylammonium Nitrate

Abstract

The microstructure and rheological properties of micellar solutions of Pluronic block copolymers (PEO x –PPO y –PEO x ) in deuterated ethylammonium nitrate (dEAN, a protic ionic liquid) are studied by small- and ultrasmall-angle neutron scattering (SANS and USANS), fluorescence microscopy, and shear rheology. A homologous series of three Pluronics with similar PPO block length (F127 (PEO106–PPO70–PEO106), P123 (PEO20–PPO70–PEO20), and L121 (PEO5–PPO70–PEO5)) are examined to explore the effect of the relative balance of solvophilic to solvophobic block size on the self-assembled microstructure. Both F127 and P123 form spherical micelles in dEAN that assemble into face-centered and body-centered cubic supramolecular crystals, respectively, upon increasing concentration or temperature. The transition from disordered to crystalline (ordered) structures manifests as a sol–gel rheological transition. A richer phase diagram is observed in the L121/dEAN system: due to its low solvophilicity in dEAN, L121 self-assembles into structures with low curvatures, namely, vesicles in the dilute regime, elongated (wormlike) micelles at intermediate concentrations and low temperatures, a nematic phase in concentrated solutions, and multilamellar phases at high temperatures. Highly viscoelastic solutions are created by the self-assembly of entangled L121 wormlike micelles. Structural length scales of the three Pluronic/dEAN systems in the various mesophases are determined from SANS and USANS.

Gas Solubility and Rheological Behavior of Natural Deep Eutectic Solvents (NADES) via Combined Experimental and Molecular Simulation Techniques

“…It can be seen that the trend of studied DES viscosity profiles is very similar to that of common ILs reported in the literature, where the viscosities of all DESs decreased with increasing temperature . It is also observed that the alternation of the hydrogen bond donor (i. e. LA, MA, CA and Fr) effects the dynamic viscosity of the produced DES as it can be seen that the highest recorded viscosity at room temperature belong to [ChCl]:[CA] (1003100 mPa s) followed by [ChCl]:[MA] (44079 mPa s).…”

“…It can be seen that the trend of studied DES viscosity profiles is very similar to that of common ILs reported in the literature, where the viscosities of all DESs decreased with increasing temperature. [71][72][73][74][75] It is also observed that the alternation of the hydrogen bond donor (i. e. LA, MA, CA and In industrial applications, some of these high viscous DES required preheating before processing and need more pumping energy as well. A rheological property that gives indication about this is the yield stresses for the produced DES systems at different temperatures.…”

Temperature-dependent self-assembly and rheological behavior of a thermoreversible pmma-PnBA-PMMA triblock copolymer gel

“…In a mid‐block selective solvent, the end‐blocks associate to form a gel‐like material above a critical micelle concentration. Many thermoreversible gels based on these principles have been investigated, but in most of the cases such investigations were limited to a small temperature window, that is, from room temperature to above the gelation temperature . However, in practical applications, gel samples can be subjected to wide temperature variations.…”

Enhanced energy transfer efficiency and stability of europium β-diketonate complex in ionic liquid-based lyotropic liquid crystals

“…[30][31][32][33] The choice of the PF 6 À anion in IL was based on the consideration of its relatively larger molecular volume and weaker coordination ability with respect to lanthanide cations, than the more commonly used bis(trifluoromethylsulfonyl)amine ion (Tf 2 N À ), which was helpful to increase the stability of europium complexes. P123 was employed owing to its excellent self-assembling property in ILs.…”