Fig. 1

Schematics of self-propelling boat: (a) three-dimensional configuration; (b) side view; (c) cross section of rotating LCE rod; (d) current state of bend LCE rod; (e) force analysis on LCE rod-blade assembly; (f) force analysis on self-propelling boat. Due to uneven temperature distribution across cross section of rod caused by heating on right side, center of gravity shifts, generating driving moment that causes rod to rotate. This rotation in turn drives blade, resulting in self-propulsion of boat (color online)"

Table 1

Material properties and geometric parameters"

Table 2

Dimensionless parameters"

Fig. 2

First-order temperature field component in cross section of LCE rod: (a) p¯=0.03; (b) p¯=0.06; (c) p¯=0.09 (R¯=0.15, ω¯=0.1); (d) R¯=0.05; (e) R¯=0.1; (f) R¯=0.15 (p¯=0.09, ω¯=0.2); (g) ω¯=0.5; (h) ω¯=1; (i) ω¯=1.5 (p¯=0.09, R¯=0.15). Higher values of p¯ lead to higher temperature fields. R¯ has no noticeable effects on temperature distribution, while larger values of ω¯ result in more uniform temperature fields (color online)"

Fig. 3

Effects of photothermal power and thermal expansion coefficient on lateral curvature: (a) contour plot of dimensionless lateral curvature with angular velocity and photothermal power; (b) contour plot of dimensionless lateral curvature with angular velocity and thermal expansion coefficient. Increasing either photothermal power or thermal expansion coefficient leads to larger lateral curvature (color online)"

Fig. 4

Effects of photothermal power and thermal expansion coefficient on driving moment: (a) contour plot of dimensionless driving moment with angular velocity and photothermal power; (b) contour plot of dimensionless driving moment with angular velocity and thermal expansion coefficient. Driving moment increases with increasing photothermal power and thermal expansion coefficient (color online)"

Fig. 5

Effects of photothermal power on self-propulsion: (a) self-rotation angular velocity ω¯ and self-propulsion speed V¯ versus photothermal power p¯; (b) relationship between driving moment M¯drive and angular velocity ω¯ for different photothermal powers p¯. Both angular velocity and self-propulsion speed increase with photothermal power p¯ (color online)"

Fig. 6

Effects of support span on self-propulsion: (a) self-rotation angular velocity ω¯ and self-propulsion speed V¯ versus support span L¯s; (b) relationship between driving moment M¯drive and angular velocity ω¯ for different support spans L¯s. Both self-rotation angular velocity and self-propulsion speed increase with increasing support span L¯s (color online)"

Fig. 7

Effects of thermal expansion coefficient on self-propulsion: (a) self-rotation angular velocity ω¯ and self-propulsion speed V¯ versus thermal expansion coefficient α¯; (b) relationship between driving moment M¯drive and angular velocity ω¯ for different thermal expansion coefficients α¯. As thermal expansion coefficient α¯ increases, both self-rotation angular velocity and self-propulsion speed increase (color online)"

Fig. 8

Effects of damping coefficient of boat on self-propulsion: (a) self-rotation angular velocity ω¯ and self-propulsion speed V¯ versus damping coefficient of boat β¯2; (b) relationship between driving moment M¯drive and angular velocity ω¯ for different damping coefficients of boat β¯2. As damping coefficient of boat β¯2 increases, self-rotation angular velocity and self-propulsion speed decrease (color online)"

Fig. 9

Effects of damping coefficient of blade on self-propulsion: (a) angular velocity ω¯ and self-propulsion speed V¯ versus damping coefficient of blade β¯1; (b) relationship between driving moment M¯drive and angular velocity ω¯ for different damping coefficients of blade β¯1. As damping coefficient of blade β¯1 increases, self-rotation angular velocity of LCE rod decreases while boat’s self-propulsion speed increases (color online)"

Fig. 10

Effects of radius on self-propulsion: (a) self-rotation angular velocity ω¯ and self-propulsion speed V¯ versus radius R¯; (b) relationship curve between driving moment M¯drive and angular velocity ω¯ for different radii R¯. As radius R¯ increases, self-rotation angular velocity and self-propulsion speed decrease (color online)"

Fig. 11

Fabrication of LCE rod: (a) chemical structure of components; (b) process flow for preparing monodomain LCE rod via two-stage mercaptoacrylate Michael addition and photopolymerization[80]. The process commences with loose cross-linking of mixture using cylindrical mold, followed by complete cross-linking through uniaxial stretching and UV irradiation (color online)"

Fig. 12

Light-powered self-propelling of LCE-based boat (see Video S1 of electronic supplementary material, https://doi.org/10.1007/s10483-026-3378-8). LCE rod self-rotates under static light and actuates blade, propelling boat to move forward (color online)"

Fig. 13

Dependence of steady-state self-propulsion speed on light power. Self-propulsion speed increases monotonically with light power, in good agreement with theoretical predictions (color online)"