Experimental Section a) Materials Aniline monomer (ACS reagent 99.5 %), ammonium persulfate (ACS reagent 98%), ≥ ≥ hydrochloric acid (37 w %), low molecular weight sodium alginate, calcium chloride and ethanol solvent were purchased from Sigma-Aldrich and were of analytical grade. All aqueous solutions were prepared using Milli-Q water (Millipore, resistivity 18.2 M Ω•cm at 25°C). b) Bipolar modification on electroconductive PANi-alg beads Asymmetric modifications were performed at room

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... ure, in a polypropylene electrochemical cell with a distance of 1.5 cm between the feeder electrodes and the electroconductive PANi-alg beads positioned in between. The feeder electrodes were platinum and gold plates for anode and cathode respectively. The cell was filled with 1 mM NH 4 Cl ethanol solution and the electric field was applied using a DC power supply. The choice of medium for the bipolar electrochemistry is due to the fact that we want to prevent solvent exchange during the exposure to the electric field. As the final beads need to be loaded with ethanol for the motion it is convenient to use ethanol also during this step. NH 4 Cl is used as an electrolyte soluble in ethanol in order to allow current to flow. A potential of 100V has been applied between the two feeder electrodes, corresponding to an electric field Electronic Supplementary Material (ESI) for Soft Matter. This journal is