Fig. 3: Optical and thermal characterization of responsive pigment dispersal for single and multicell system.

a Multicell device: (i) outer expandable layer; (ii) adhesive and gasket; (iii) fluidic pigment layer; (iv) inner rigid plate; (v) digitally-driven peristaltic pump; (vi) light intensity sensor; (vii) feedback loop between sensor and pump. b Optical spectrum for pigment fluid (aqueous carbon black, black line) and castor oil (grey line). c Experimental setup for data in (d–f): (i) light source; (ii) single light sensor. d Images showing dispersal and contraction sequence for multicell devices as a response to light. Scale bar is 10 cm. e Light intensity as a function of time for single sequence in (d). f Three sequences of (e) to demonstrate consistency. g Experimental setup for data in (h–j): (i) light source; (ii) dispersed pigment fluid layer; (iii) light sensor; (iv) signal to digital peristaltic pump; (v) control over pigment fluid dispersal. h Images showing dispersal and contraction sequence for single-cell device as a response to light. Scale bar is 15 cm. i Light intensity as a function of time for single sequence in (h). j Three sequences of (i) to demonstrate consistency. k Experimental setup for data in (l–n): (i) heat source; (ii) dispersed pigment fluid layer; (iii) thermocouple measuring interior plate; (iv) signal to digital peristaltic pump; (v) control over pigment fluid dispersal. l Images showing dispersal and contraction sequence for single-cell facade as a response to temperature. Scale bar is 15 cm. m Temperature as a function of time for single sequence in (l). n Three sequences of (m) to demonstrate consistency. Grey line represents control curve, where pigment fluid is dispersed and maintained statically across all three cycles.