Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Innovative combination of hard and soft materials improves adhesion to rough surfaces

11.09.2018

Adhesion is involved whenever industrial components are moved to and from without any residues being left behind. But the surfaces of these objects are never completely smooth. Even those surfaces that appear smooth to the human eye tend to be rough when observed under a microscope. Scientists at the Leibniz Institute for New Materials developed a new adhesive structure so that adhesion, even to these types of rough surfaces, can be reliably provided. They combined hard and soft materials within this structure. They determined that the combination of hard and soft materials adheres significantly better to rough surfaces compared to structures produced from only a single soft material.

As a result, industrial handling processes can be improved and made safer, and that is not all. The materials are also promising in terms of on-skin applications, such as self-adhesive wound closures or “wearables” - networked computers that can be applied directly to the skin.


The large-scale model shows basic principle and structure of the new adhesives, where soft materials (yellow) are applied to harder materials.

Source: Iris Maurer; free within this press release

The scientists presented their findings in the renowned scientific journal Applied Materials &Interfaces. Co-author René Hensel is now going to receive the Adhesion Innovation Award in recognition of this publication. This award is co-organized by EURADH (European Adhesion Conference) and FEICA (Association of the European Adhesive & Sealant Industry).

As part of their investigations, the research scientists developed two-millimeter pillars as a model system and brought these into contact with rough surfaces. The measured force required to peel the pillar away again is the measure of the adhesion.

... more about:
»INM »adhesion »coating »pillars »soft materials »surfaces

“The pillars that we used were made of a hard material but their ends had a layer of soft plastic. In order to peel away this pillar, we needed to apply a force that was five times greater compared to peeling away a pillar composed entirely of the soft material. Therefore, it clearly adheres better,” explains René Hensel, the Deputy Head of the Functional Microstructures program division.

The research scientists established during the investigations that the quality of adhesion corresponds to the softness and thinness of the coating applied to the ends of the pillars. The softer the material, the better its ability to adapt to rough surfaces. The fact that adhesive strength correlates to how thin the coating is goes hand in hand with the delayed formation of cracks during contact: The adhesive structure detaches from the surface whenever a crack forms.

These cracks take longer to form due to reduced stress peaks. As a result, cracks and detachment only occur under higher loads. “Surprisingly, the thinner the coating is, the more pronounced this phenomenon,” adds Hensel. Adhesion is also affected by the shape - how two materials of varying hardness are combined. A rounded boundary layer between both materials improves adhesion. This also appears to affect the formation of cracks.

The thickness of the soft coating should simultaneously match the degree of roughness: “The surface of woodchip wallpaper is far rougher than skin, for instance, so in order for something to adhere to woodchip wallpaper, a much thicker soft coating must be selected compared to adhesion to skin,” says Hensel. The research scientists are currently very interested in adhesion to skin. This is central to future research as it appears to play a particularly important role in the development of “wearables” as well as for treating wounds.

Wissenschaftliche Ansprechpartner:

Your expert at INM:

Dr. René Hensel
Deputy Head Functional Microstructures
Phone: +49681-9300-390
rene.hensel@leibniz-inm.de

Originalpublikation:

Sarah C. L. Fischer, Eduard Arzt, and René Hensel, „Composite Pillars with a Tunable Interface for Adhesion to Rough Substrates”, ACS Appl. Mater. Interfaces, 2017, 9 (1), pp 1036–1044, DOI: 10.1021/acsami.6b11642; https://pubs.acs.org/doi/10.1021/acsami.6b11642

Dr. Carola Jung | idw - Informationsdienst Wissenschaft
Further information:
http://www.inm-gmbh.de

Further reports about: INM adhesion coating pillars soft materials surfaces

More articles from Materials Sciences:

nachricht World's first passive anti-frosting surface fights ice with ice
18.09.2018 | Virginia Tech

nachricht A novel approach of improving battery performance
18.09.2018 | Ulsan National Institute of Science and Technology (UNIST)

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Patented nanostructure for solar cells: Rough optics, smooth surface

Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.

"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...

Im Focus: New soft coral species discovered in Panama

A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.

Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...

Im Focus: New devices based on rust could reduce excess heat in computers

Physicists explore long-distance information transmission in antiferromagnetic iron oxide

Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets.

Im Focus: Finding Nemo's genes

An international team of researchers has mapped Nemo's genome

An international team of researchers has mapped Nemo's genome, providing the research community with an invaluable resource to decode the response of fish to...

Im Focus: Graphene enables clock rates in the terahertz range

Graphene is considered a promising candidate for the nanoelectronics of the future. In theory, it should allow clock rates up to a thousand times faster than today’s silicon-based electronics. Scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) and the University of Duisburg-Essen (UDE), in cooperation with the Max Planck Institute for Polymer Research (MPI-P), have now shown for the first time that graphene can actually convert electronic signals with frequencies in the gigahertz range – which correspond to today’s clock rates – extremely efficiently into signals with several times higher frequency. The researchers present their results in the scientific journal “Nature”.

Graphene – an ultrathin material consisting of a single layer of interlinked carbon atoms – is considered a promising candidate for the nanoelectronics of the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

One of the world’s most prominent strategic forums for global health held in Berlin in October 2018

03.09.2018 | Event News

4th Intelligent Materials - European Symposium on Intelligent Materials

27.08.2018 | Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

 
Latest News

Making better use of enzymes: a new research project at Jacobs University

19.09.2018 | Life Sciences

Light provides spin

19.09.2018 | Physics and Astronomy

Enjoying virtual-reality-entertainment without headache or motion sickness

19.09.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>