J. mater. chem. B J. mater. chem. B Photomechanical response under physiological conditions of azobenzene-containing 4D-printed liquid crystal elastomer actuators Ceamanos L. Mulder D. J. Kahveci Z. López-Valdeolivas M. Schenning A. P. H. J. Sánchez-Somolinos C. 2023 research-article