While it is quite well established that the complex morphologies of Planetary Nebulae are often due to the presence of companion(s), AGB stars are often assumed to be single and spherical. Detecting companions around AGB stars is difficult as those stars pulsate and are embedded in dust, making radial velocity detections difficult. Interaction with a binary companion can however be detected via its morphological imprint in the envelopes.

I will present an imaging/polarimetry survey with SPHERE/VLT, leading to the sharpest direct images ever of AGB stars' envelopes. We imaged the envelopes of these stars with a resolution down to ~15milliarcsec, and measured the polarimetric properties of the envelopes with the same resolution. The polarisation we see is due to scattering by dust, so that any asymmetry in the dust distribution is enhanced in our polarimetric maps. So far we mapped ~30 AGB stars.Most of the envelopes imaged show a clear departure from spherical symmetry and in some cases, clear signs of interactions with a companion are observed. I will discuss how these companions can influence the ejection of the envelopes.