Paper Number
PO119 

Session
Poster Session

Title
Structure and rheology of binary Pluronic block copolymer mixtures in the protic ionic liquid ethylammonium nitrate

Presentation Date and Time
October 8, 2014 (Wednesday) 6:05

Track / Room
Poster Session / Poster

Authors (Click on name to view author profile)

1. Chen, Ru (University of Delaware, Department of Chemical and Biomolecular Engineering)
2. López-Barrón, Carlos R. (ExxonMobil Chemical Company)
3. Wagner, Norman J. (University of Delaware, Department of Chemical and Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Ru Chen¹, Carlos R. López-Barrón², and Norman J. Wagner^1
1Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19711; ²ExxonMobil Chemical Company, Baytown, TX

Speaker / Presenter 
Chen, Ru

Text of Abstract
The structural and rheological properties of a model series of binary Pluronic block copolymer mixtures dissolved in a protic ionic liquid are studied as a strategy to modulate and control the soft solid behavior of amphiphilic block copolymers in ionic liquids. The properties of the soft solids are controlled via tuning the mixture composition of Pluronic block copolymers P123 and F127 self-assembled in deuterated ethylammonium nitrate (dEAN). Equilibrium microstructures are studied by linear viscoelasticity and small angle neutron scattering (SANS), while the shear induced microstructures are probed by in situ rheo-SANS in the radial direction (1-3 plane of flow) under steady and oscillatory shear flow using recently developed time resolved methods [1, 2]. Solutions with total Pluronic composition of 27.5 wt% and 50/50 mass ratio of P123/F127 in dEAN form closed packed micellar phases similar to those formed in parent homopolymers [3]. The application of shear flow in a Couette geometry leads to layering of the closed packed phases . It was also observed that relatively low amplitude oscillations induces slightly different ordering than steady shear. This study points out a strategy for modification of the structural, and hence rheological, properties of Pluronic block copolymers in ionic liquid solvent, providing insights useful for comparing the properties of self-assembled amphiphilic block copolymers in molecular versus ionic liquid solvents under rest as well as steady and dynamic oscillatory shear flows. References: [1] C. R. López-Barrón et al. Physical Review Letters, 2012, 108, 258301. [2] A. P. R. Eberle and L. Porcar, Current Opinion in Colloid & Interface Science, 2012, 17, 33-43. [3] G. E. Newby et al. Journal of Colloid and Interface Sicence, 2009, 329, 54-61.