Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A new way to combine soft materials

01.03.2018

Technique paves the way for more complex soft devices

Every complex human tool, from the first spear to latest smartphone, has contained multiple materials wedged, tied, screwed, glued or soldered together. But the next generation of tools, from autonomous squishy robots to flexible wearables, will be soft. Combining multiple soft materials into a complex machine requires an entirely new toolbox -- after all, there's no such thing as a soft screw.


An unmodified hydrogel (left) peels off easily from an elastomer. A chemically-bonded hydrogel and elastomer (right) are tough to peel apart, leaving residue behind.

Image courtesy of Suo Lab/Harvard SEAS

Current methods to combine soft materials are limited, relying on glues or surface treatments that can restrict the manufacturing process. For example, it doesn't make much sense to apply glue or perform surface treatment before each drop of ink falls off during a 3D printing session.

But now, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a new method to chemically bond multiple soft materials independent of the manufacturing process. In principle, the method can be applied in any manufacturing processes, including but 3D printing and coating. This technique opens door to manufacturing more complex soft machines.

The research is published in Nature Communications.

"This technique allows us to bond various hydrogels and elastomers in various manufacturing processes without sacrificing the properties of the materials," said Qihan Liu, a postdoctoral fellow at SEAS and co-first author of the paper. "We hope that this will pave the way for rapid-prototyping and mass-producing biomimetic soft devices for healthcare, fashion and augmented reality."

The researchers focused on the two most-used building blocks for soft devices, hydrogels (conductors) and elastomers (insulators). To combine the materials, the team mixed chemical coupling agents into the precursors of both hydrogels and elastomers. The coupling agents look like molecular hands with small tails. As the precursors form into material networks, the tail of the coupling agents attaches to the polymer networks, while the hand remains open.

When the hydrogel and elastomer are combined in the manufacturing process, the free hands reach across the material boundary and shake, creating chemical bonds between the two materials. The timing of the "handshake" can be tuned by multiple factors such as temperature and catalysts, allowing different amounts of manufacturing time before bonding happens.

The researchers showed that the method can bond two pieces of casted materials like glue but without applying a glue layer on the interface. The method also allows coating and printing of different soft materials in different sequences. In all cases, the hydrogel and elastomer created a strong, long-lasting chemical bond.

"The manufacturing of soft devices involves several ways of integrating hydrogels and elastomers, including direct attachment, casting, coating, and printing," said Canhui Yang, a postdoctoral fellow at SEAS and co-first author of the paper. "Whereas every current method only enables two or three manufacturing methods, our new technique is versatile and enables all the various ways to integrate materials."

The researchers also demonstrated that hydrogels -- which as the name implies are mostly water -- can be made heat resistant in high temperatures using a bonded coating, extending the temperature range that hydrogel-based device can be used. For example, a hydrogel-based wearable device can now be ironed without boiling.

"Several recent findings have shown that hydrogels can enable electrical devices well beyond previously imagined," said Zhigang Suo, Allen E. and Marilyn M. Puckett Professor of Mechanics and Materials at SEAS and senior author of the paper. "These devices mimic the functions of muscle, skin, and axon. Like integrated circuits in microelectronics, these devices function by integrating dissimilar materials. This work enables strong adhesion between soft materials in various manufacturing processes. It is conceivable that integrated soft materials will enable spandex-like touchpads and displays that one can wear, wash, and iron."

###

This research was co-authored by Guodong Nian and Shaoxing Qu of Zhejiang University. It was supported by the National Science Foundation through the Harvard Material Research Science and Engineering Center (MRSEC).

Media Contact

Leah Burrows
lburrows@seas.harvard.edu
617-496-1351

 @hseas

http://www.seas.harvard.edu/ 

Leah Burrows | EurekAlert!

Further reports about: Harvard SEAS coating elastomers hydrogels manufacturing process soft materials

More articles from Materials Sciences:

nachricht Graphene origami as a mechanically tunable plasmonic structure for infrared detection
25.04.2018 | University of Illinois College of Engineering

nachricht Scientists create innovative new 'green' concrete using graphene
24.04.2018 | University of Exeter

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Why we need erasable MRI scans

New technology could allow an MRI contrast agent to 'blink off,' helping doctors diagnose disease

Magnetic resonance imaging, or MRI, is a widely used medical tool for taking pictures of the insides of our body. One way to make MRI scans easier to read is...

Im Focus: BAM@Hannover Messe: innovative 3D printing method for space flight

At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.

Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

World's smallest optical implantable biodevice

26.04.2018 | Power and Electrical Engineering

Molecular evolution: How the building blocks of life may form in space

26.04.2018 | Life Sciences

First Li-Fi-product with technology from Fraunhofer HHI launched in Japan

26.04.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>