TY - JOUR
T1 - Diffusion-Based Height Analysis Reveals Robust Microswimmer-Wall Separation
AU - Ketzetzi, Stefania
AU - De Graaf, Joost
AU - Kraft, Daniela J.
PY - 2020/12/2
Y1 - 2020/12/2
N2 - Microswimmers typically move near walls, which can strongly influence their motion. However, direct experimental measurements of swimmer-wall separation remain elusive to date. Here, we determine this separation for model catalytic microswimmers from the height dependence of the passive component of their mean-squared displacement. We find that swimmers exhibit "ypsotaxis,"a tendency to assume a fixed height above the wall for a range of salt concentrations, swimmer surface charges, and swimmer sizes. Our findings indicate that ypsotaxis is activity induced, posing restrictions on future modeling of their still-debated propulsion mechanism.
AB - Microswimmers typically move near walls, which can strongly influence their motion. However, direct experimental measurements of swimmer-wall separation remain elusive to date. Here, we determine this separation for model catalytic microswimmers from the height dependence of the passive component of their mean-squared displacement. We find that swimmers exhibit "ypsotaxis,"a tendency to assume a fixed height above the wall for a range of salt concentrations, swimmer surface charges, and swimmer sizes. Our findings indicate that ypsotaxis is activity induced, posing restrictions on future modeling of their still-debated propulsion mechanism.
UR - http://www.scopus.com/inward/record.url?scp=85097531140&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.125.238001
DO - 10.1103/PhysRevLett.125.238001
M3 - Article
C2 - 33337216
AN - SCOPUS:85097531140
SN - 0031-9007
VL - 125
JO - Physical Review Letters
JF - Physical Review Letters
IS - 23
M1 - 238001
ER -