Manipulation of functional nano-matters in fluids

Abstract

The ability to manipulate a nanoscale object in fluids affects diverse fields as materials science, nanotechnology, and biomedicine. Although many clever trapping and manipulating techniques have been devised, new methods are still in great demand for handling different materials and geometries. Here I present new nanotechnological methods recently reported: 1) scanning-aperture electrostatic tweezers and 2) light-driven self-propelled nanodiamonds. First, I will discuss a new trapping technique for charged nanoparticles in fluids, that is, a geometry-induced electrostatic trap that exploits a scannable nanopipette to create nanoscale electrostatic potential well [1]. This technique enables contact-free, damage-free, field-free size-independent trapping of very small single nanoparticles (10 nm) and can be a basic platform for fundamental studies on soft matter physics, biophysics, optonanofludics, and plasmonics [2]. Second, I will discuss the realization of an “active” nanodiamond (ND) swimmer [3] in fluids, composed of a ND crystal a light-driven self-thermophoretic micromotor. The locomotion of the ND swimmer - from translational to rotational motion - is controlled by shape-dependent hydrodynamic interactions. The precise engineering of its shape is achieved by glancing angle physical vapor deposition [4]. In addition, I shall briefly introduce ND swimmer’s new sensing capabilities combined with active transport including, potentially, in living organisms. References 1. J. T. Kim, S. Spindler, V. Sandoghdar, Nature Communications 5, 3380 (2014). 2. Y. Tuna*, J. T. Kim*, H.-W. Liu, V. Sandoghdar (in preparation). 3. J. T. Kim*, U. Chudhury*, H.-H. Jeong, P. Fischer, Advanced Materials (submitted). 4. A. G. Mark, J. G. Gibbs, T.-C. Lee, P. Fischer, Nature Materials 12, 802 (2013). (*co-first authors)