fig4

Figure 4. Physical methods of electrode formation. (A) IPMC sputtered with titanium or chromium between Au electrodes and the matrix. Reproduced with permission from Ref.^[68]. Copyright^© 2017 Elsevier B.V. (B) Electrodes with biological hair structure prepared by solution casting. Reproduced with permission from Ref.^[73]. Copyright^© 2022 American Chemical Society. (C) A novel actuator prepared by hot-pressing. Reproduced with permission from Ref.^[75]. Copyright^© 2011 American Chemical Society. (D) Method of spraying the silver nanowire solution on the surface of Nafion. Reproduced with permission from Ref.^[35]. Copyright^© 2020 The Royal Society of Chemistry.