Table 3.

Summary of structural color actuators with structural color and surface topography changes

Material	Stimuli	Mechanism	Actuation	Structural color	Sensitivity	Ref.
CLC network/poly(benzyl acrylate)	Temperature	Embossing and shape memory	Height increasing	Blue to red	0–55 °C	79
BPLC network	Temperature	Embossing and shape memory	Height increasing	Blue to red	0–40 °C	80
CLCE	Temperature	Embossing with rough surface and shape memory	Rough to smooth surface	Reflection intensity decreasing	10–40 °C	81
CLC polymer particles/polymer binder	Temperature	Two-step embossing and shape memory	Height increasing, diffractive grating topography to smooth	Rainbow effect vanishing; blue to green	20–50–75 °C	82
Interpenetrating LC-hydrogel networks	Humidity/pH	Absorption of water causes pitch change, pattern	Surface topography change	497–650 nm; 563– 730 nm	RH: 6%–85% pH: 3–9	83
CLC network with hydrogen bonds	Water	Absorption of water causes pitch change, pattern	Thickness increasing	520– 720 nm	Water	84
CLC network	Water	CLC network swelling in water	Flat to non-flat surface	Blue to red	Water or breath	85
CLCE/LCN semi-interpenetrating network	Temperature	cholesteric-to-isotropic transition causes reflection intensity decreasing; crosslink density difference-induced thermal expansion difference causes topography change	Pillars to valleys	Reflection intensity decreasing	Color: 30–120 °C; Topography: 24–50 °C	86