87 citations · 255 across the 13 of their papers we have counts for
13 papers
Writing in Water
Nadir Möller, Lukas Hecht, Ran Niu +2
Writing is an ancient communication technique dating back at least 30,000 years. While even sophisticated contemporary writing techniques hinge on solid surfaces for engraving or t…
Self-solidifying active droplets showing memory-induced chirality
Kai Feng, José Carlos Ureña Marcos, Aritra K. Mukhopadhyay +4
Most synthetic microswimmers do not reach the autonomy of their biological counterparts in terms of energy supply and diversity of motion. Here we report the first all-aqueous drop…
Unraveling Modular Microswimmers: From Self-Assembly to Ion-Exchange Driven Motors
Benno Liebchen, Ran Niu, Thomas Palberg +1
Active systems contain self-propelled particles and can spontaneously self-organize into patterns making them attractive candidates for the self-assembly of smart soft materials. O…
Modular approach to microswimming
Ran Niu, Thomas Palberg
The field of active matter in general and microswimming in particular has experienced a rapid and ongoing expansion over the last decade. A particular interesting aspect is provide…
Colloidal electro-phoresis in the presence of symmetric and asymmetric electro-osmotic flow
Denis Botin, Jennifer Wenzl, Ran Niu +1
We characterize the electro-phoretic motion of charged sphere suspensions in the presence of substantial electro-osmotic flow using a recently introduced small angle super-heterody…
Seedless assembly of colloidal crystals by inverted micro-fluidic pumping
Ran Niu, Thomas Palberg
We propose a simple seedless approach to assemble millimeter sized monolayer single colloidal crystals with desired orientations at predetermined locations on an unstructured charg…
Large scale Micro-Photometry for high resolution pH-characterization during electro-osmotic pumping and modular micro-swimming
Ran Niu, Stanislav Khodorov, Julian Weber +2
Micro-fluidic pumps as well as artificial micro-swimmers are conveniently realized exploiting phoretic solvent flows based on local gradients of temperature, electrolyte concentrat…
Formation of a transient amorphous solid in low density aqueous charged sphere suspensions
Ran Niu, Sabrina Heidt, Ramsia Sreij +3
Colloidal glasses form from hard spheres, nearly hard spheres, ellipsoids and platelets or their attractive variants have been studied in detail. Complementing and checking theoret…
Self-assembly of colloidal molecules due to self-generated flow
Ran Niu, Thomas Speck, Thomas Palberg
The emergence of structure through aggregation is a fascinating topic and of both fundamental and practical interest. Here we demonstrate that self-generated solvent flow can be us…
Controlled assembly of single colloidal crystals using electro-osmotic micro-pumps
Ran Niu, Erdal C. Oğuz, Hannah Müller +4
We assemble charged colloidal spheres at deliberately chosen locations on a charged unstructured glass substrate utilizing ion exchange based electro-osmotic micro-pumps. Using mic…
Assembly and speed control in ion exchange based modular phoretic micro-swimmers
Ran Niu, Denis Botin, Julian Weber +2
We report an experimental study on ion-exchange based modular micro-swimmers in low-salt water. Cationic ion-exchange particles and passive cargo particles assemble into self-prope…
Microfluidic Pumping by Micromolar Salt Concentrations
Ran Niu, Patrick Kreissl, Aidan T. Brown +5
An ion-exchange-resin-based microfluidic pump is introduced that utilizes trace amounts of ions to generate fluid flows. We show experimentally that our pump operates in almost dei…
To make a glass - avoid the crystal
Thomas Palberg, Eckhard Bartsch, Richard Beyer +5
Colloidal model systems allow for a flexible tuning of particle sizes, particle spacings and mutual interactions at constant temperature. Colloidal suspensions typically crystalliz…