Maxim Paliy

Facile One-Step Photolithographic Method for Engineering Hierarchically Nano/Microstructured Transparent Superamphiphobic Surfaces

It is of great value to develop a simple, controllable, and scalable method of making superamphiphobic surfaces. Here we present a facile one-step photolithographic method to engineer superamphiphobic surfaces consisting of photoresist micropillars decorated with nanoparticles of the same photoresist. The surface or coating is optically transparent and versatile, and can be fabricated on a broad range of substrates including stretchable elastomers. During the development of the micropillar array, photoresist nanoparticles are spontaneously grown on the micropillars by a well-controlled emulsification process of the un-cross-linked residual photoresist. This creates a hierarchical structure with a re-entrant and convex morphology which is the key for superoleophobicity. The chemical bonding between the nanoparticles and the micropillars is strong producing a robust and durable coating. This facile method is scalable and industry-applicable for a variety of applications such as self-cleaning, antifouling, and deicing/antifrosting.

EXTREMELY SHORT OPTICAL PULSES IN CARBON NANOTUBES IN DISPERSIVE NONMAGNETIC DIELECTRIC MEDIA

We consider Maxwell equations for an electromagnetic field propagating in carbon nanotubes (CNTs) placed on a dispersive nonmagnetic dielectric medium. We obtain the effective equation analogous to the classical sine-Gordon equation. Then it has been analyzed numerically. We have revealed the dependence of the pulse on the type of CNT and on the initial pulse amplitude, as well as on the medium dispersion constants.

Cleaving C–H bonds with hyperthermal H2: facile chemistry to cross-link organic molecules under low chemical- and energy-loads

A facile method for cross-linking organic molecules has been developed by computational modeling, instrumentation design, and experimental research. Briefly, organic molecules are hit by H2 with controllable kinetic energy in our novel apparatus where a high flux of hyperthermal H2 is generated. When a C–H bond of the organic molecule is hit by H2 at about 20 eV, efficient kinematic energy-transfer in the H2→H collision facilitates the C–H dissociation with nearly 100% reaction probability. When H2 hits other atoms which are by nature much heavier than H2, mass disparity bars effective energy transfer and this both blocks undesirable bond dissociation and reduces unnecessary energy wastage. The recombination of the carbon radicals generated by the C–H cleavage efficiently completes the production of C–C cross-links at room temperature with no additional energy/chemicals requirements. In addition to these green chemistry merits, this new method is better than other cross-linking techniques which rely on prerequisite reactions to add cross-linkers to the organic molecules or additional reactants and additives. These promising features are validated by several cross-linking trials which demonstrate desirable mechanical, electrical, chemical, and biochemical changes while inducing no undesirable damage of chemical functionalities in the original molecules.

The possibility of using RNA for optical applications

Based on computer simulation, it is proposed that so-called RNA nanotubes, which are sequences of bonded RNA nanorings, be used for optical applications in manufacturing metamaterials. A recently developed model of coarse-grained RNA is used that allows the study of key properties of RNA nanotubes. The Langevin method is used to discover the basic thermodynamic and mechanical properties of nanotubes and their response to an external field.

On the vortex stability in BEC

The exotic quantum phenomenon of Bose–Einstein condensation (BEC) is the key ingredient in a new type of laser that emits atoms rather than photons, and that promises to revolutionize atom optics. In this paper, we consider the possibility of stable angular momentum transfer by an atom laser beam which should be more useful in various applications than a circularly polarized photon laser. The most promising way to assign the initial angular momentum is the outcoupling from the BEC cloud in a vortex state. However, the question of the vortex stability (metastability) arises as well as stability of the beam angular momentum. Here we propose a method for the solution of this problem by developing a quasi-hydrodynamic approach to the condensate with account of its interaction with the non-condensed atoms. Using the concept of local hydrodynamical invariants, we further derive the necessary conditions for the beam, such that the initial angular momentum is transferred conservatively. Both continuous and pulsed schemes are considered.