Complex Three-dimensional Nanostructures Research Articles

Plastic Deformation Drives Wrinkling, Saddling, and Wedging of Annular Bilayer Nanostructures

We describe the spontaneous wrinkling, saddling, and wedging of metallic, annular bilayer nanostructures driven by grain coalescence in one of the layers. Experiments revealed these different outcomes based on the dimensions of the annuli, and we find that the essential features are captured using finite element simulations of the plastic deformation in the metal bilayers. Our results show that the dimensions and nanomechanics associated with the plastic deformation of planar nanostructures can be important in forming complex three-dimensional nanostructures.

Self-assembly of zinc hydroxide/dodecyl sulfate nanolayers into complex three-dimensional nanostructures by laser ablation in liquid

Three-dimensional zinc hydroxide/dodecyl sulfate (Zn(OH) 2/DS) nanostructures self-assembled by nanolayers have been fabricated by pulsed laser ablation of bulk Zn in ethanol–water solution of sodium DS. The presence of ethanol causes defects in the hydroxyl group sites of Zn(OH) 2 that partially form ZnO structures, which facilitate heterogeneous nucleation of secondary nanolayers, resulting in three-dimensional nanostructures. These results demonstrate that laser ablation in liquid can be used to fabricate complex nanostructures by controlling the nucleation and growth behavior of laser-produced species.

The Polyvalent Gold Nanoparticle Conjugate-Materials Synthesis, Biodiagnostics, and Intracellular Gene Regulation.

Advances in nanoscale directed assembly strategies have enabled researchers to analogize atomic assembly via chemical reactions and nanoparticle assembly, creating a new nanoscale "periodic table." We are just beginning to realize the nanoparticle equivalents of molecules and extended materials and are currently developing the ground rules for creating programmable nanometer-scale coordination environments. The ability to create a diverse set of nanoscale architectures from one class of nanoparticle building blocks would allow for the synthesis of designer materials, wherein the physical properties of a material could be predicted and controlled a priori. Our group has taken the first steps toward this goal and developed a means of creating tailorable assembly environments using DNA-nanoparticle conjugates. These nanobioconjugates combine the discrete plasmon resonances of gold nanoparticles with the synthetically controllable and highly selective recognition properties of DNA. Herein, we elucidate the beneficial properties of these materials in diagnostic, therapeutic, and detection capabilities and project their potential use as nanoscale assembly agents to realize complex three-dimensional nanostructures.

Structure, function, and self-assembly of single network gyroid ( I 4 1 32) photonic crystals in butterfly wing scales

Complex three-dimensional biophotonic nanostructures produce the vivid structural colors of many butterfly wing scales, but their exact nanoscale organization is uncertain. We used small angle X-ray scattering (SAXS) on single scales to characterize the 3D photonic nanostructures of five butterfly species from two families (Papilionidae, Lycaenidae). We identify these chitin and air nanostructures as single network gyroid (I4(1)32) photonic crystals. We describe their optical function from SAXS data and photonic band-gap modeling. Butterflies apparently grow these gyroid nanostructures by exploiting the self-organizing physical dynamics of biological lipid-bilayer membranes. These butterfly photonic nanostructures initially develop within scale cells as a core-shell double gyroid (Ia3d), as seen in block-copolymer systems, with a pentacontinuous volume comprised of extracellular space, cell plasma membrane, cellular cytoplasm, smooth endoplasmic reticulum (SER) membrane, and intra-SER lumen. This double gyroid nanostructure is subsequently transformed into a single gyroid network through the deposition of chitin in the extracellular space and the degeneration of the rest of the cell. The butterflies develop the thermodynamically favored double gyroid precursors as a route to the optically more efficient single gyroid nanostructures. Current approaches to photonic crystal engineering also aim to produce single gyroid motifs. The biologically derived photonic nanostructures characterized here may offer a convenient template for producing optical devices based on biomimicry or direct dielectric infiltration.

Fabrication of complex three-dimensional nanostructures using focused ion beam and nanomanipulation

In this article, the authors present a fabrication/assembly method that grants the ability to create complex three-dimensional (3D) nanostructures. This method uses a combination of micro- and nanomachining capabilities with a focused ion beam (FIB) and six degrees of freedom (DOFs) 3D nanomanipulator. A dual beam of scanning electron microscope and a FIB system was used to ion beam mill a silicon piece in order to create tethered structures. Various 3D structures were further processed by the ion beam milling process and platinum chemical vapor deposition unit to form sub-100-nm features. The gas assisted deposition system was used to create a convex shape on the nanoairplane using the gray scale image digital patterning system. The six DOFs nanomanipulator was used to pick, rotate, and place the nanoflags onto the FIB defined Texas and United States maps made by the FIB. In addition, a multiwalled carbon nanotube was used as a flag pole, and then it was attached to a scanning probe microscope tip. The tip was then actuated to tapping mode to demonstrate the nanoflag waving. The assembly technique was also utilized to manipulate individual 100 nm polystyrene microspheres.

The role of helium ion microscopy in the characterisation of complex three-dimensional nanostructures

This work addresses two major issues relating to Helium Ion Microscopy (HeIM). First we show that HeIM is capable of solving the interpretation difficulties that arise when complex three-dimensional structures are imaged using traditional high lateral resolution techniques which are transmission based, such as scanning transmission electron microscopy (STEM). Secondly we use a nano-composite coating consisting of amorphous carbon embedded in chromium rich matrix to estimate the mean escape depth for amorphous carbon for secondary electrons generated by helium ion impact as a measure of HeIM depth resolution.

Crystallographically-oriented nanoassembly by ZnS tricrystals and subsequent three-dimensional epitaxy

Chemistry gives us the ability to manipulate atoms and molecules into nanometer and micrometer scale building blocks, while the science of crystallography is concerned with the spatial arrangement of atoms, ions, and molecules and thus the morphology and structures of materials. Complex three-dimensional ZnS nanostructures have been fabricated via step-by-step crystallographically-controlled chemical processes. Tricrystals of ZnS whiskers were prepared via a controlled thermal evaporation process, and then the tricrystals were thermally treated in an atmosphere formed by evaporating B-N-O precursors into N2/NH3 to afford BN-coated arrays of nanobranches. The ZnS nanobranches grew epitaxially on the ternary facets and extended in three [0001] directions forming ordered nanostructures. Meanwhile, the protecting insulating sheath of BN formed on the ZnS nanostructures confined the growth of the nanospines and enhanced their stability. The method may be extended to fabricate other semiconductor nanomaterials with novel structures.

DNA IN ANOTHER DIMENSION

USING DNA as a basic chemical building block rather than a genetic molecule, scientists have devised a method for creating complex three-dimensional nanostructures with precisely controlled dimensions that range from 10 to 100 nm ( Nature 2009, 459 , 414). The strategy of self-assembly could provide a general route for manufacturing sophisticated devices with nanoscale features, the researchers say. The technique, developed by William M. Shih of Boston’s Dana-Farber Cancer Institute and colleagues, is an extension of DNA origami, in which hundreds of short oligonucleotides fasten to a long single strand of DNA in such a way that it folds into a predetermined shape (C&EN, March 20, 2006, page 10). Researchers have already used the technique to create 2-D snowflakes and smiley faces, as well as a 3-D DNA box (C&EN, May 11, page 30). Shih’s strategy allows nanotechnologists to build a vast diversity of 3-D DNA structures, a capability his group demonstrated by constructing a ...

Fabrication of Complex Three-Dimensional Nanostructures from Self-Assembling Block Copolymer Materials on Two-Dimensional Chemically Patterned Templates with Mismatched Symmetry

A study is presented of the self-assembly of a lamella-forming blend of a diblock copolymer and its respective homopolymers on periodically patterned substrates consisting of square arrays of spots, that preferentially attract one component, as a function of pattern dimensions and film thickness. The blend morphology follows the pattern at the substrate and forms a single quadratically perforated lamella (QPL). At intermediate film thicknesses necks connect this QPL to the film surface, resulting in a bicontinuous morphology. The necks do not register with the underlying square lattice but exhibit a substantial amount of hexagonal short-range order. For thicker films we observe bicontinuous morphologies consisting of parallel lamellae with disordered perforations. These results demonstrate a promising strategy for the fabrication of complex interfacial nanostructures from two-dimensional chemically patterned templates.

Complex gold nanostructures derived by templating from diatom frustules

Diatom frustules have been used for the first time as templates for the fabrication of gold nanostructures; high-precision replicas featuring complex three-dimensional gold nanostructures from the nano- to the microscale were achieved.

Fabricating complex three-dimensional nanostructures with high-resolution conformable phase masks.

High-resolution, conformable phase masks provide a means to fabricate, in an experimentally simple manner, classes of 3D nanostructures that are technologically important but difficult to generate in other ways. In this approach, light passing through a phase mask that has features of relief comparable in dimension to the wavelength generates a 3D distribution of intensity that exposes a photopolymer film throughout its thickness. Developing this polymer yields a structure in the geometry of the intensity distribution, with feature sizes as small as 50 nm. Rigorous coupled-wave analysis reveals the fundamental aspects of the optics associated with this method; a broad-range 3D nanostructures patterned with it demonstrates its technical capabilities. A nanoporous filter element built inside a microfluidic channel represents one example of the many types of functional devices that can be constructed.

Three-dimensional micro- and nanostructuring with two-photon polymerisation

Two-photon polymerisation (2PP) of inorganic-organic hybrid polymers (ORMOCER1s) is demonstrated as a very promising approach for the fabrication of complex three-dimensional micro and nanostructures. Optical and mechanical properties of ORMOCER1 together with the 2PP-process open up new options for the design and packaging, e.g. of photonic devices. The 2PP-process employs ultrashort pulses which are focused into the volume of a photopolymer, being transparent at the laser wavelength. Solidification is performed in a highly localised volume due to the quadratic dependence of the two-photon absorption rate on the laser intensity. The polymerisation occurs along the 3D-trace of the focus allowing the fabrication of any computer generated 3D-structure by direct laser "recording". This technology can be used for rapid prototyping and low-cost fabrication of micro- and nanostructured components. Achieving spatial resolutions down to ~100 nm, even optical components can be produced and integrated to compact devices. This paper provides a discussion of two-photon polymerisation technique and examples of microfabrication.

Porphyrin-based nanostructures: routes to molecular electronics

The potential of porphyrins and related macrocycles for applications in molecular electronics owes much to the fundamental studies of the photosynthetic light-harvesting arrays and reaction centers. The use of model systems to better understand these essential processes has resulted in the development of an assortment of methodologies for functionalizing and constructing the complex three-dimensional nanostructures that will be essential for a successful molecular electronic system.