fig1

Figure 1. Summary of research on gel-based materials and devices. The three types of gels are hydrogels (e.g., super-absorbent hydrogels (reproduced with permission^[30]. Copyright 2019, Elsevier), integrated hydrogels under variant deformations (reproduced with permission^[31]. Copyright 2020, Elsevier) and adhesive hydrogels (reproduced with permission^[32]. Copyright 2021, Elsevier)), ionogels (e.g., stretchable organic-ionogels (reproduced with permission^[33]. Copyright 2022, Elsevier), highly conductive ionogels (reproduced with permission^[34]. Copyright 2016, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) and flame-retardant organic ionogels (reproduced with permission^[35]. Copyright 2019, American Chemical Society)) and aerogels (e.g., lightweight aerogels (reproduced with permission^[36]. Copyright 2018, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim), highly porous aerogels (reproduced with permission^[37]. Copyright 2022, American Chemical Society) and thermally insulating aerogels (reproduced with permission^[38]. Copyright 2022, American Chemical Society)). Six primary application directions, namely, living things, healthcare, prosthesis, human-machine interactions, electronic skin, and tissue engineering, are also illustrated (reproduced with permission^[39]. Copyright 2020, Royal Society of Chemistry).