Table 1 Comparison of full model with two hydrodynamics-only models.

From: Topographical pathways guide chemical microswimmers

Model

Best fit parameters

heq/R , no gravity

θ eq , no gravity

heq/R , with gravity

θ eq , with gravity

Full model

binert/bcap=0.3, bwall/bcap=−0.2, bcap<0

1.11

77.9°

1.06

94.8°

Squirmer, first two squirming modes only

B2/B1=0.3

1.64

102°

Below 1.02

Around 45°

Effective squirmer

binert/bcap=−0.8, bcap<0

1.063

69.7°

1.09

65.3°

  1. For each model, we list the parameters that give the best fit to the experimental observations. For each model and set of best-fit parameters, we give the height and orientation of the particle when it is in a ‘sliding state’ above a planar wall in both the presence of gravity (corresponding to motion above a substrate) and the absence of gravity (corresponding to motion near a side wall). Experimentally, it is observed that θeq≈90° in both cases. Of the three models, the full model shows the best fit with these experimental observations. For the squirmer with only the first two squirming modes, there are clear signs of an attractor with heq/R below the numerical cutoff of h/R=1.02 in the presence of gravity, but this attractor has θeq far from 90° (see also Supplementary Note 3 and Supplementary Table 1). The best-fit effective squirmer agrees moderately well with the experimental observations. However, the orientation of the sliding seems significantly different from the experiment and, as discussed in Supplementary Note 3 and Supplementary Table 2, the best-fit parameters correspond to an unrealistically large force dipole.
Back to article page