Functional Nanomaterials Chair

Current research of our group

 

This is a concise selection of our current work. For a detailed overview of our scientific work, you can refer to our publications. You can find our latest publications here

2021

Modification of Nylon Nets with Poly(dimethylsiloxane)/Tetrapodal-Shaped ZnO Composite for Aquaculture Biofouling Control

 

ACS_APM

About the Cover:
The nylon nets were modified with polydimethylsiloxane/tetrapodal-shaped ZnO composite for aquaculture biofouling control. The modified nets show good biofouling control performance in the field test where the attached organisms can be easily and completely removed by low cleaning pressure.

 

Full paper: Link

Electrically powered repeatable air explosions using microtubular graphene assemblies

Materials Today

 

About the Cover:
Controllable rapid expansion and activation of gases is important for a variety of applications, including combustion engines, thrusters, actuators, catalysis, and sensors. Typically, the activation of macroscopic gas volumes is based on ultra-fast chemical reactions, which require fuel and are irreversible. An “electrically powered explosion”, i.e., the rapid increase in temperature of a macroscopic relevant gas volume induced by an electrical power pulse, is a feasible repeatable and clean alternative, providing adaptable non-chemical power on demand. Till now, the fundamental problem was to find an efficient transducer material that converts electrical energy into an immediate temperature increase of a sufficient gas volume. To overcome these limitations, we developed electrically powered repeatable air explosions (EPRAE) based on free-standing graphene layers of nanoscale thickness in the form of microtubes that are interconnected to a macroscopic framework. These low-density and highly permeable graphene foams are characterized by heat capacities comparable to air. The EPRAE process facilitates cyclic heating of cm3-sized air volumes to several 100 °C for more than 100,000 cycles, heating rates beyond 300,000 K s−1 and repetition rates of several Hz. It enables pneumatic actuators with the highest observed output power densities (>40 kW kg−1) and strains ∼100%, as well as tunable microfluidic pumps, gas flowmeters, thermophones, and micro-thrusters.

 

Full paper: Link 

Press Release: Link

 

Nanoscale-Sculptured Al Microparticles as Universal Hierarchical Adhesion Promoters

PSS RRL

 

About the Cover:
The adhesion between two non-stick polymers can be significantly increased through hierarchical mechanical interlocking by using a low amount of nanoscale-sculptured Al microparticles with hook-like structures at the polymer interface. Our approach demonstrated in this work has the potential to be used as an environmentally friendly universal adhesion promoter for nonstick polymers and can be easily applied at an industrial scale.

 

Full paper: Link

 

 

Light-Controlled Growth Factors Release on Tetrapodal ZnO-Incorporated 3D-Printed Hydrogels for Developing Smart Wound Scaffold

  

 

About the Cover:
We present a 3D printed smart wound scaffold encapsulating growth factors decorated with light-sensitive and antibacterial tetrapodal zinc oxide (t-ZnO) microparticles for the treatment of chronic wounds. The multifunctional pro perties of the smart scaffold combined with light-triggered angiogenic factor release, antibacterial properties, and tissue compatibility enable fast wound recovery.

 

Full paper: Link

Press release: "Smart plaster could accelerate the healing of chronic wounds"

Microengineered Hollow Graphene Tube Systems Generate Conductive Hydrogels with Extremely Low Filler Concentration

Nano Letters

About the Cover:
We present an approach for the preparation of hydrogel composites with outstanding electrical conductivity at extremely low filler loadings. Exfoliated graphene and polyacrylamide are microengineered to 3D composites such that conductive graphene pathways pervade the hydrogel matrix, similar to an artificial nervous system.

 

Full paper: Link

Press release: "Like an artificial nervous system"

 

2020

Formation of micro-mechanical interlocking sites by nanoscale sculpturing for composites or hybrid materials with stainless steel

 

  JMR

The demands of modern materials are highly challenging as well as partially contradictory. For example, materials should be strong like steels but chemically inert like soft low-surface energy polymers. These conflicts can be overcome by effectively combining disparate materials in composites that allow fusing of the traditional material classes like ceramics, polymers, and metals. Such combinations require sufficient adhesion between the individual materials. If adhesion is based on mechanical interlocking, the chemistry and chemical compatibility of the individual materials play a negligible role for the adhesion, but the mechanical properties of the materials are exclusively important. This work focusses on a technologically relevant example of a micro-mechanical interlocking surface structure on grade 304 stainless steel (SST) by nanoscale sculpturing. Using a low aggressive/low toxic seawater-like and diluted HNO3-based electrolyte, the resulting structure is free from preferential grain-boundary etching. The sculptured surface is super hydrophilic with undercuts suitable for mechanical interlocking with polymers. In single-lap shear tests, different two-component adhesives failed cohesively on structured SST while showing more than a doubling of the ultimate shear strength compared to the state-of-the-art grit-blasted SST composites which only showed adhesive failure.

Full paper: Link

 

3D printer sensors could make breath tests for diabetes possible

The production of highly sensitive sensors is usually a complex process: it requires many different steps and the almost dust-free environment of special cleanrooms. Together with the Biomedical Engineering at the Technical University of Moldova we have now developed a procedure to produce extremely sensitive and energy-efficient sensors using 3D printing. The simple and cost-effective production method is also suitable for industrial production, as we have recently explained in the renowned specialist journal Nano Energy. Our sensor, is able to precisely measure the concentration of acetone vapor using a special structuring at nano level. As the acetone concentration in the breath correlates with blood sugar levels, we hope to have made a step towards producing a breath test for diabetics that could replace the daily checking of their blood sugar levels by finger pricks.

Full paper: Link

Press release: "3D printer sensors could make breath tests for diabetes possible"

 

 

Macroscopic Silicone Microchannel Matrix for Tailored Drug Release and Localized Glioblastoma Therapy

ABSTRACT: Localized therapy of the highly malignant brain tumor glioblastoma multiforme (GBM) could help to drastically improve the treatment efficiency and increase the patient’s median survival. Here, a macroscopic PDMS matrix composed of interconnected microchannels for tailored drug release and localized GBM therapy is introduced. Based on a simple bottomup fabrication method using a highly versatile sacrificial template, the presented strategy solves the scaling problem associated with the previously developed microchannel-based drug delivery systems, which were limited to two dimensions due to the commonly employed top-down microfabrication methods. Additionally, tailoring of the microchannel density, the fraction of drug-releasing microchannels and the macroscopic size of the drug delivery systems enabled precise adjustment of the drug release kinetics for more than 10 days. As demonstrated in a long-term GBM in vitro model, the release kinetics of the exemplarily chosen GBM drug AT101 could be tailored by variation of the microchannel density and the initial drug concentration, leading to diffusion-controlled AT101 release. Adapting a previously developed GBM treatment plan based on a sequential stimulation with AT101, measured anti-tumorigenic effects of free versus PDMS-released AT101 were comparable in human GBM cells and demonstrated efficient biological activity of PDMS-released AT101.

 

Full paper: Link

Press release: "Reducing side effects during the treatment of brain tumours "

 

Innovative battery research SH: Start of a new project “BAEW – Labor für zuverlässige, batteriegestützte Energiewandlung”

 

Innovative battery technology paired with the right power electronics has the potential to fundamentally improve our energy generation and mobility. As batteries are more and more in focus, new materials solution for high energy and high power batteries are necessary. Silicon as one of the earth abundant materials is the material of choice having the potential to drastically increase the capacity and thus energy density of batteries.
Therefore, this project aims to bring together specialists in the field of battery development from materials science and power electronics in a real laboratory with a new research infrastructure. In this innovation laboratory, in close mutual cooperation, new battery technology can be tested in application-related power electronics issues related to memory integration in smart grids and electromobility. In addition, the use of "Wide Band Gap" (WBP) power semiconductors (silicon carbide in the stationary area and gallium nitride in mobile applications) forms the heart of the project. In particular, the new infrastructure will offer regional prospects for high-quality research, cooperation and training in the future. Locally rooted and well-trained specialists in turn benefit the economy in Schleswig-Holstein and promote the transfer of knowledge between universities and industry.
In the course of the energy transition, the areas of electricity, heat and mobility are growing together. A reliable energy supply requires both intelligent power grids and innovative storage technologies. To achieve this, the areas of materials science and power electronics will work closely together in a new laboratory at the Kiel University (CAU). Schleswig-Holstein invests almost two million euros in the equipment to develop and test new battery systems for intelligent networks and electromobility. The interdisciplinary laboratory at the Faculty of Engineering is also open for scientific and industrial cooperation. Additionally, this laboratory should be integrated in the daily education of young researchers in Schleswig-Holstein. On Thursday, July 2, 2020, 9:45 a.m., Prime Minister Daniel Günther hands over the funding decision of 1,974,034 euros funded by the “Europäischer Fonds für regionale Entwicklung (EFRE)”.

 

Press release CAU: Forschungskooperation für neue Batterietechnik

 

2019

 

Artificial heart valves: new coating procedure could reduce risk of thrombosis

 

Heart valves regulate the blood flow, to ensure the body is supplied with enough blood. If they don’t close properly any more, for example due to a heart attack, then artificial heart valves can fulfil the required function. But blood platelets can easily stick to the metal surfaces of conventional heart valves. In order to prevent the formation of blood clots, patients must therefore take medication for life. Certain blood-repellent plastics could offer alternative materials. However, until now they have been too soft to be used as a heart valve. A research team from the Institute for Materials Science at Kiel University (CAU), in cooperation with the University Medical Center Schleswig-Holstein (UKSH), Campus Lübeck, has now managed to combine a soft, blood-repellent plastic with a sturdy plastic. The team is convinced it could be used for biomedical implants such as artificial heart valves in future. The research team has presented how they used the simple, purely mechanical procedure to permanently connect non-adhesive plastics for the first time in the journal Nanoscale Horizons. The technique for joining is based on mechanical interlocking and is enabled by creating micrscopic hooking point on the stiff polymer's surface. To these the soft, non-sticky plastic can adhere. Such a microscopic hooking point can be seen below.

 

Link paper: Perfect polymer interlocking by spherical particles: capillary force shapes hierarchical composite undercuts

Press release CAU: Artificial heart valves: new coating procedure could reduce risk of thrombosis

 

2016

 

Making metal surfaces strong, resistant, and multifunctional by nanoscale-sculpturing
 

Surfaces are the crucial and limiting factor in nearly all metal applications, especially when technologically relevant alloys are employed. Insufficient surface properties on the nano- and microscale of metals determine, e.g. metal–polymer composite stability, implant biocompatibility, or corrosion resistance. Conventional surface preparation is just like an arbitrary cut through the metal body optimized for bulk behavior so that such surfaces contain various element mixtures and complex microstructures in which grains and lattice planes vary in their chemical stability from weak to strong. In contrast, the here described novel nanoscale-surface sculpturing based on semiconductor etching knowledge turns surfaces of everyday metals into their most stable configuration, but leaves the bulk properties unaffected. Thus, nanoscale-sculpturing ensures stronger, reliable joints to nearly all materials, reduces corrosion vastly, and generates a multitude of multifunctional surface properties not limited to those shown below.

Zwei Studenten und eine Tasse Kaffee
 

Link paper: http://pubs.rsc.org/en/content/articlepdf/2016/nh/c6nh00140h
 

Press release CAU: http://www.uni-kiel.de/pressemeldungen/?pmid=2016-285-nanosculpturing&lang=en


 


Zinc oxide cures genital herpes in animals

  

A new effective vaccine for the protection from genital herpes has been developed from a microbicide and four-legged zinc oxide microstructures calles tetrapods. The viral particles are bound to the zinc oxide particles where the antigen presenting cells can further process them. This has been a cooperative work with the University of Illinois at Chicago

Link to the paper Link to press release

 

 Antigen presenting cells (APC)  process viral particles, which are bound on zinc oxide tetrapods (ZOTEN) Credit: Deepak Shukla

Antigen presenting cells (APC)  process viral particles, which are bound on zinc oxide tetrapods (ZOTEN) Credit: Deepak Shukla

2015

Functional Ecofriendly Coatings for Marine Applications
 

Biofouling auf verschiedenen Oberflächen in Gammel Âlbo, Dänemark

Biofouling on a varying surfaces at Gammel Âlbo, Denmark

Since the prohibition of tributyltin (TBT)-based antifouling paints in 2008, the development of environmentally compatible and commercially realizable alternatives is a crucial issue. Cost effective fabrication of antifouling paints with desired physical and biocompatible features is simultaneously required and recent developments in the direction of inorganic nanomaterials could play a major role. In the present work, a solvent free polymer/particle-composite coating based on two component polythiourethane (PTU) and tetrapodal shaped ZnO (t-ZnO) nano- and microstructures has been synthesized and studied with respect to mechanical, chemical and biocompatibility properties. Furthermore, antifouling tests have been carried out in artificial seawater tanks. Four different PTU/t-ZnO composites with various t-ZnO filling fractions (0 wt%, 1 wt%, 5 wt%, 10 wt%) were prepared and the corresponding tensile, hardness, and pull-off test results revealed that the composite filled with 5 wt% t-ZnO exhibits the strongest technical properties. Surface free energy (SFE) studies using contact angle measurements showed that the SFE value decreases with an increase in t-ZnO filler amounts. The influence of t-ZnO on the polymerization reaction was confirmed by Fourier transform infrared-spectroscopy measurements and thermogravimetric analysis. The immersion tests demonstrated that fouling behavior of the PTU/t-ZnO composite with a 1 wt% t-ZnO filler has been decreased in comparison to pure PTU. The composite with a 5 wt% t-ZnO filler showed almost no biofouling.

 

Antifoulung

For marine applications, the antifouling coatings have to fulfill various demands, like mechanical and UV-stability, being non-toxic and long lasting, etc. The presented investigations demonstrate the suitability of tetrapodal ZnO-polymer composite coatings for antifouling applications.



 

2014



Zwei Studenten und eine Tasse Kaffee
 Mechanical interlocking as adhesion process on special, etched aluminium substrates 
a)-d) The increase of the surface roughness leads to locking of the glue or adhesive e) An adhesionsystem between
silicones which enables painting on silicone surfaces f) Special, etched aluminium surfaces g) 3D-printed polymerlocks
on etched surfaces exhibit an extremely strong adhesion.