From single to multi: Spatiotemporally controlled 4D printing poly(urethane–urea) elastomers via topological reconfiguration - Jianfeng Xie; Hangyu Shen; Kai Zhou; Junhui Gong; Chongyang Cai; Yuanbin Mao; Xianqiang Pei; Xinrui Zhang; Shoubing Chen; Qihua Wang; Yaoming Zhang (Chemical Engineering Journal, 2026)