The structure, rheological response, and ionic conductivity of ABA brush block copolymer (BBCP) ion gels containing 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMI][TFSI]) at polymer concentrations spanning 5-50 wt % (Phi(gel)) were studied by small angle X-ray scattering, dynamic mechanical analysis, and AC impedance spectroscopy. Application of a hard sphere form factor and Percus-Yevick structure factor reveals trends in gel micellar structure as a function of BBCP molecular weight, A block volume fraction (Phi(A)), and Phi(gel). Viscoelastic properties are strongly dependent on end-block molar mass, with storage moduli <= 10(3) Pa at 25 degrees C. Impedance measurements reveal near liquid-like dynamics in the matrix phase as evidenced by conductivities near 1 mS/cm at 25 degrees C that decrease with increasing Phi(gel) and Phi(A). (C) 2015 Wiley Periodicals, Inc.