Long-term stability of aerophilic metallic surfaces underwater.

Aerophilic surfaces immersed underwater trap films of air known as plastrons. Plastrons have typically been considered impractical for underwater engineering applications due to their metastable performance. Here, we describe aerophilic titanium alloy (Ti) surfaces with extended plastron lifetimes that are conserved for months underwater.

Magnetic Quincke rollers with tunable single-particle dynamics and collective states.

Electrohydrodynamically driven active particles based on Quincke rotation have quickly become an important model system for emergent collective behavior in nonequilibrium colloidal systems. Like most active particles, Quincke rollers are intrinsically nonmagnetic, preventing the use of magnetic fields to control their complex dynamics on the fly. Here, we report on magnetic Quincke rollers based on silica particles doped with superparamagnetic iron oxide nanoparticles.

Shaping Liquid Droplets on an Active Air-Ferrofluid Interface.

An air-liquid interface is important in many biological and industrial applications, where the manipulation of liquids on the air-liquid interface can have a significant impact. However, current manipulation techniques on the interface are mostly limited to transportation and trapping. Here, we report a magnetic liquid shaping method that can squeeze, rotate, and shape nonmagnetic liquids on an air-ferrofluid interface with programmable deformation.

Motion and trapping of micro- and millimeter-sized particles on the air-paramagnetic-liquid interface.

Understanding the motion of particles on an air-liquid interface can impact a wide range of scientific fields and applications. Diamagnetic particles floating on an air-paramagnetic-liquid interface are previously known to have a repulsive motion from a magnet. Here, we show a motion mechanism where the diamagnetic particles floating on the air-paramagnetic-liquid interface are attracted and eventually trapped at an off-center distance from the magnet.

Tunable and Magnetic Thiol-ene Micropillar Arrays.

Tunable and responsive surfaces offer routes to multiple functionalities ranging from superhydrophobic surfaces to controlled adhesion. Inspired by cilia structure in the respiratory pathway, magnetically responsive periodic arrays of flexible and magnetic thiol-ene micropillars are fabricated. Omnidirectional collective bending of the pillar array in magnetic field is shown.

Formation of Nanospikes on AISI 420 Martensitic Stainless Steel under Gallium Ion Bombardment.

The focused ion beam (FIB) has proven to be an extremely powerful tool for the nanometer-scale machining and patterning of nanostructures. In this work, we experimentally study the behavior of AISI 420 martensitic stainless steel when bombarded by Ga ions in a FIB system. The results show the formation of nanometer sized spiky structures.

Phase transitions as intermediate steps in the formation of molecularly engineered protein fibers.

A central concept in molecular bioscience is how structure formation at different length scales is achieved. Here we use spider silk protein as a model to design new recombinant proteins that assemble into fibers. We made proteins with a three-block architecture with folded globular domains at each terminus of a truncated repetitive silk sequence.