Assembling epoxy, one of the most common and widely used thermosets, by welding with remote control is extremely difficult and has not been realized so far, as epoxy cannot melt or be dissolved. Here we present a very simple but highly efficient solution by exploring the photothermal effect of carbon nanotubes (CNTs) to manipulate the transesterification reaction in vitrimers. The carbon nanotube dispersed vitrimer epoxy presented here can be welded by light within seconds or minutes. Moreover, various CNT–vitrimer epoxy materials with different chemical compositions and physical properties can be joined together. Furthermore, transmission welding can be used to weld CNT–vitrimers with other kinds of epoxy or thermoplastic polymers, which is not applicable to welding by direct heating and impossible to realize using the currently available photoweldable covalently cross-linked polymer networks. Additionally, these networks can be efficiently healed by light without the involvement of any glue or sealing agents.

A self-floating sturdy polymer foam which by itself enables efficient solar steam generation without optical concentration.

Vitrimers are one kind of covalently crosslinked polymers that can be reprocessed. Topology freezing transition temperature (T_v) is vitrimer’s upper limit temperature for service and lower temperature for recycle. However, there has been no proper method to detect the intrinsic T_v till now. Even worse, current testing methods may lead to a misunderstanding of vitrimers. Here we provide a sensitive and universal method by doping or swelling aggregation-induced-emission (AIE) luminogens into vitrimers. The fluorescence of AIE-luminogens changes dramatically below and over T_v, providing an accurate method to measure T_v without the interference of external force. Moreover, according to this method, T_v is independent of catalyst loading. The opposite idea has been kept for a long time. This method not only is helpful for the practical application of vitrimers so as to reduce white wastes, but also may facilitate deep understanding of vitrimers and further development of functional polymer materials.

Introducing oligoaniline into a vitrimer resulted in a smart material that simultaneously responds to six different stimuli and performs six different functions.