Self-oscillating floating of a spherical liquid crystal elastomer balloon under steady illumination

•A new self-floating balloon composed of optically-responsive liquid crystal elastomer(LCE) is established.•The LCE balloon has two typical motion regimes, namely the divergence regime and self-floating regime.•The critical conditions for triggering the self-floating are analytically derived.•The amplitude and frequency of self-floating can be designed by several parameters.