Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Diffusiophoretic design of self-spinning microgears from colloidal
  microswimmers   Design strategies to assemble dissipative building blocks are essential to
create novel and smart materials and machines. We recently demonstrated the
hierarchical self-assembly of phoretic microswimmers into self-spinning
microgears and their synchronization by diffusiophoretic interactions [Aubret
\textit{et al., Nature Physics}, 2018]. In this paper, we adopt a pedagogical
approach and expose our strategy to control self-assembly and build machines
using phoretic phenomena. We notably introduce Highly Inclined Laminated
Optical sheets microscopy (HILO) to image and quantify anisotropic and dynamic
diffusiophoretic interactions, which could not be observed by standard
fluorescence microscopy. The dynamics of a (haematite) photocalytic material
immersed in (hydrogen peroxide) fuel under various illumination patterns is
first described and quantitatively rationalized by a model of diffusiophoresis,
the migration of a colloidal particle in a concentration gradient. It is
further exploited to design phototactic microswimmers, that direct towards the
high intensity of light, as a result of the the torque exerted by the haematite
in a light gradient on a microswimmer. We finally demonstrate the assembly of
self-spinning microgears from colloidal microswimmers by controlling
dissipative diffusiophoretic interactions, that we characterize using HILO and
quantitatively compare to analytical and numerical predictions. Because the
approach described hereby is generic, this works paves the way for the rational
design of machines by controlling phoretic phenomena.

9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat