4D-printed materials can be stiff as wood or soft as sponge

March 22, 2019

Imagine smart materials that can morph from being stiff as wood to as soft as a sponge - and also change shape.

Rutgers University-New Brunswick engineers have created flexible, lightweight materials with 4D printing that could lead to better shock absorption, morphing airplane or drone wings, soft robotics and tiny implantable biomedical devices. Their research is published in the journal Materials Horizons.

3D printing, also known as additive manufacturing, turns digital blueprints to physical objects by building them layer by layer. 4D printing is based on this technology, with one big difference: it uses special materials and sophisticated designs to print objects that change shape with environmental conditions such as temperature acting as a trigger, said senior author Howon Lee, an assistant professor in the Department of Mechanical and Aerospace Engineering. Time is the fourth dimension that allows them to morph into a new shape.

"We believe this unprecedented interplay of materials science, mechanics and 3D printing will create a new pathway to a wide range of exciting applications that will improve technology, health, safety and quality of life," Lee said.

The engineers created a new class of "metamaterials" - materials engineered to have unusual and counterintuitive properties that are not found in nature. The word metamaterials is derived from the Greek word "meta," which means "higher" or "beyond."

Previously, the shape and properties of metamaterials were irreversible once they were manufactured. But the Rutgers engineers can tune their plastic-like materials with heat, so they stay rigid when struck or become soft as a sponge to absorb shock.

The stiffness can be adjusted more than 100-fold in temperatures between room temperature (73 degrees) and 194 degrees Fahrenheit, allowing great control of shock absorption. The materials can be reshaped for a wide variety of purposes. They can be temporarily transformed into any deformed shape and then returned to their original shape on demand when heated.

This shows how 4D-printed smart materials can morph from stiff to soft and also change shape. Video by Chen Yang/Rutgers University-New Brunswick.

The materials could be used in airplane or drone wings that change shape to improve performance, and in lightweight structures that are collapsed for space launches and reformed in space for a larger structure, such as a solar panel.

Soft robots made of soft, flexible and rubbery materials inspired by the octopus could have variable flexibility or stiffness that is tailored to the environment and task at hand. Tiny devices inserted or implanted in people for diagnosis or treatment could be temporarily made soft and flexible for minimally invasive and less painful insertion into the body, Lee said.
The study's lead author is Chen Yang, a doctoral student in Lee's lab. Co-authors include Manish Boorugu, Andrew Dopp, Jie Ren, Raymond Martin and Daehoon Han - all current or former Rutgers students - and Professor Wonjoon Choi at the Korea University.

Rutgers University

Related Metamaterials Articles from Brightsurf:

Hyperbolic metamaterials exhibit 2T physics
According to Igor Smolyaninov of the University of Maryland, ''One of the more unusual applications of metamaterials was a theoretical proposal to construct a physical system that would exhibit two-time physics behavior on small scales.''

Origami metamaterials show reversible auxeticity combined with deformation recoverability
New research by Northwestern Engineering and Georgia Institute of Technology expands the understanding of origami structures, opening possibilities for mechanical metamaterials to be used in soft robotics and medical devices.

Temporal aiming with temporal metamaterials
Achieving a controllable manipulation of electromagnetic waves is important in many applications.

VR and AR devices at 1/100 the cost and 1/10,000 the thickness in the works
Professor Junsuk Rho of the departments of mechanical engineering and chemical engineering and doctoral student in mechanical engineering Gwanho Yoon at POSTECH with the research team at Korea University have jointly developed moldable nanomaterials and a printing technology using metamaterials, allowing the commercialization of inexpensive and thin VR and AR devices.

Virtualized metamaterials opens door for acoustics application and beyond
Scientists from the Hong Kong University of Science and Technology (HKUST) have realized what they called a virtualized acoustic metamaterial, in digitizing material response to an impulse response stored in a software program.

In acoustic waves, engineers break reciprocity with 'spacetime-varying metamaterials'
Working in an emerging field known to as 'spacetime-varying metamaterials,' University at Buffalo engineers have demonstrated the ability to break reciprocity in acoustic waves.

Induced flaws in metamaterials can produce useful textures and behavior
A new Tel Aviv University study shows how induced defects in metamaterials -- artificial materials the properties of which are different from those in nature -- also produce radically different consistencies and behaviors.

Researchers use metamaterials to create two-part optical security features
Researchers have developed advanced optical security features that use a two-piece metamaterial system to create a difficult-to-replicate optical phenomenon.

Artificial intelligence (AI) designs metamaterials used in the invisibility cloak
The research group of Prof. Junsuk Rho, Sunae So and Jungho Mun of Department of Mechanical Engineering and Department of Chemical Engineering at POSTECH developed a design with a higher degree of freedom which allows to choose materials and to design photonic structures arbitrarily by using Deep Learning.

Scientists take a 'metamaterials' approach to earthquake damage
At the SSA 2019 Annual Meeting, seismologists from around the world will discuss how metamaterial theory might be applied to everything from developing deflective barriers to manipulating the layout of buildings within a city as a way to minimize the impact of damaging surface seismic waves.

Read More: Metamaterials News and Metamaterials Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.