  Unprecedentedly massive electrorheology has been reported for dilute graphene
nanoflakes based ER fluids that have been engineered as novel, readily
synthesizable polymeric gels. Polyethylene glycol based graphene gels have been
synthesized and very high ER response, 25,000 percent enhancement in viscosity
under influence of electric field, has been observed for low concentration
systems 2 wt. percent. The gels overcome several drawbacks innate to ER fluids.
The gels exhibit long term stability, high graphene packing ratio which ensures
very high ER response and the microstructure of the gels ensure that
fibrillation of the graphene nanoflakes under field is undisturbed by thermal
fluctuations, further leading to mega ER. The gels exhibit large yield stress
handling caliber with yield stress observed as high as 13 kPa at 2 wt. perc.
graphene. Detailed investigations on the effects of graphene concentration,
electric field strength, imposed shear resistance and transients of electric
field actuation on the ER response of the gels have been performed. The gels
show nearly negligible hysteresis with respect to electro viscous effects which
speak of the stability and responsiveness required in transient situations.
Indepth analyses with explanations have been provided for the observations and
effects, such as sheet over-crowding induced loss of structural integrity at
high concentrations and inter flake lubrication or slip induced augmented ER
response. The present gels show great promise as potential ER gels for variant
smart applications, such as damping and vibration control in active aircraft
and vehicle structures, micronanoscale electroactuation, in suspensions or
braking clutching in high performance specialized vehicular systems, etc.
