Matthias Worgull

Bio: Matthias Worgull is an academic researcher from Karlsruhe Institute of Technology. The author has contributed to research in topics: Embossing & Molding (process). The author has an hindex of 23, co-authored 98 publications receiving 1424 citations.

3D Direct Laser Writing of Nano‐ and Microstructured Hierarchical Gecko‐Mimicking Surfaces

Abstract: Applying 3D direct laser writing, artificial hierarchical gecko-type structures are designed and fabricated down to nanometer dimensions. In this way, the elastic modulus and the length scale of the gecko's setae are very closely matched. Direct laser writing is a very flexible rapid prototyping method allowing the fabrication of arbitrary nanostructures. Since the parameters of the structures can be easily changed, this technique is perfect for design studies of dry adhesives. Measuring the adhesional forces by atomic force microscopy, the influence of several design parameters like density, aspect ratio, and tip-shape on dry adhesion performance are systematically examined. In this way, it is revealed that hierarchy is favorable for artificial gecko-inspired dry adhesives made of stiff materials on the nanometer scale.

Liquid Glass: A Facile Soft Replication Method for Structuring Glass.

Abstract: Liquid glass is a photocurable amorphous silica nanocomposite that can be structured using soft replication molds and turned into glass via thermal debinding and sintering. Simple polymer bonding techniques allow the fabrication of complex microsystems in glass like microfluidic chips. Liquid glass is a step toward prototyping of glass microstructures at low cost without requiring cleanroom facilities or hazardous chemicals.

Large-scale hot embossing

Abstract: The hot embossing process is a flexible molding technique to produce delicate microstructures with high aspect ratios on thin layers. Large-scale hot embossing is one effective way to meet future requirements and produce high-quality microstructures at low costs. For this, however, principal changes of the molding process and molding tool design will be required. In the present paper, constructive solutions for large-scale hot embossing shall be described. Based on a simulation of the hot embossing process, solutions shall be presented that are aimed at reducing shrinkage of the molded parts and demolding forces and, hence, at avoiding damages of microstructures during demolding.

Bioinspired air-retaining nanofur for drag reduction.

Abstract: Bioinspired nanofur, covered by a dense layer of randomly distributed high aspect ratio nano- and microhairs, possesses superhydrophobic and air-retaining properties. Nanofur is fabricated using a highly scalable hot pulling method in which softened polymer is elongated with a heated sandblasted plate. Here we investigate the stability of the underwater air layer retained by the irregular nanofur topography by applying hydraulic pressure to the nanofur kept underwater, and evaluate the gradual changes in the air-covered area. Furthermore, the drag reduction resulting from the nanofur air retention is characterized by measuring the pressure drop across channels with and without nanofur.

Glassomer-Processing Fused Silica Glass Like a Polymer.

Abstract: Fused silica glass is one of the most important high-performance materials for scientific research, industry, and society. However due to its high chemical and thermal resistance as well as high hardness, fused silica glass is notoriously difficult to structure. This work introduces Glassomer, a solid nanocomposite, which can be structured using polymer molding and subtractive technologies at submicrometer resolution. After polymer processing Glassomer is turned into optical grade fused silica glass during a final heat treatment. The resulting glass has the same optical transparency as commercial fused silica and a smooth surface with a roughness of a few nanometers. This work makes high-performance fused silica glass components accessible to high-throughput fabrication technologies and will enable numerous optical, photonic and medical applications in science and industry.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Structural (n,m) determination of isolated single wall carbon nanotubes by resonant Raman scattering

Abstract: We show that the Raman scattering technique can give complete structural information for one-dimensional systems, such as carbon nanotubes. Resonant confocal micro-Raman spectroscopy of an (n,m) individual single-wall nanotube makes it possible to assign its chirality uniquely by measuring one radial breathing mode frequency omega(RBM) and using the theory of resonant transitions. A unique chirality assignment can be made for both metallic and semiconducting nanotubes of diameter d(t), using the parameters gamma(0) = 2.9 eV and omega(RBM) = 248/d(t). For example, the strong RBM intensity observed at 156 cm(-1) for 785 nm laser excitation is assigned to the (13,10) metallic chiral nanotube on a Si/SiO2 surface.

Review on micro molding of thermoplastic polymers

Abstract: Molding of micro components from thermoplastic polymers has become a routinely used industrial production process. This paper describes both the more than 30-year-old history and the present state of development and applications. Hot embossing, injection molding, reaction injection molding, injection compression molding, thermoforming, and various types of tool fabrication are introduced and their advantages and drawbacks are discussed. In addition, design considerations, process limitations, and commercially available micro molding machines are presented.