Nav: Home

New technique enables 3-D printing with paste of silicone particles in water

June 07, 2017

Using the principles behind the formation of sandcastles from wet sand, North Carolina State University researchers have achieved 3-D printing of flexible and porous silicone rubber structures through a new technique that combines water with solid and liquid forms of silicone into a pasty ink that can be fed through a 3-D printer. The finding could have biomedical applications and uses in soft robotics.

In a paper published this week in Advanced Materials, corresponding author Orlin Velev and colleagues show that, in a water medium, liquid silicone rubber can be used to form bridges between tiny silicone rubber beads to link them together -- much as a small amount of water can shape sand particles into sandcastles.

Interestingly, the technique can be used in a dry or a wet environment, suggesting that it has the potential to be used in live tissue - think of an ultraflexible mesh encapsulating a healing droplet, or a soft bandage that can be applied or even directly printed on some portion of the human body, for example.

"There is great interest in 3-D printing of silicone rubber, or PDMS, which has a number of useful properties," said Velev, INVISTA Professor of Chemical and Biomolecular Engineering at NC State. "The challenge is that you generally need to rapidly heat the material or use special chemistry to cure it, which can be technically complex.

"Our method uses an extremely simple extrudable material that can be placed in a 3-D printer to directly prototype porous, flexible structures - even under water," Velev added. "And it is all accomplished with a multiphasic system of just two materials - no special chemistry or expensive machinery is necessary. The 'trick' is that both the beads and the liquid that binds them are silicone, and thus make a very cohesive, stretchable and bendable material after shaping and curing."
-end-
The paper is co-authored by first author Sangchul Roh, an NC State Ph.D. candidate; NC State graduate student Dishit Parekh; Bhuvnesh Bharti, a faculty member at Louisiana State University; and Dr. Simeon Stoyanov of Wageningen University in The Netherlands.

The research is funded by the National Science Foundation under grant CBET-1604116 and by the Research Triangle Materials Research Science and Engineering Center on Programmable Soft Matter under grant DMR-1121107. NC State has filed a provisional patent on the new technique.

Note to editors: An abstract of the paper follows.

"Three-dimensional printing by multiphase silicone/water capillary inks" Authors: Sangchul Roh, Dishit Parekh and Orlin D. Velev, North Carolina State University; Bhuvnesh Bharti, Louisiana State University; Simeon Stoyanov, Wageningen University

Published: June 7, 2017, online in Advanced Materials

DOI: 10.1002/adma.201701554

Abstract: Three-dimensional (3D) printing of polymers is accomplished easily with thermoplastics as the extruded hot melt solidifies rapidly during the printing process. Printing with liquid polymer precursors is more challenging due to their longer curing times. One curable liquid polymer of specific interest is polydimethylsiloxane (PDMS). We demonstrate a new efficient technique for 3D-printing with PDMS by using a capillary suspension ink containing PDMS in the form of both pre-cured microbeads and uncured liquid precursor, dispersed in water as continuous medium. The PDMS microbeads are held together in thixotropic granular paste by capillary attraction induced by the liquid precursor. The resulting capillary ink could be 3D printed and cured both in air and under water. These PDMS structures are remarkably elastic and flexible, and could find a broad range of applications in soft materials and biomedical microarchitectures.

North Carolina State University

Related Water Articles:

Water, water, nowhere
Researchers at the University of Pittsburgh's Swanson School of Engineering have found that the unusual properties of graphane -- a two-dimensional polymer of carbon and hydrogen -- could form a type of anhydrous 'bucket brigade' that transports protons without the need for water, potentially leading to the development of more efficient hydrogen fuel cells for vehicles and other energy systems.
Advantage: Water
When water comes in for a landing on the common catalyst titanium oxide, it splits into hydroxyls just under half the time.
What's really in the water
Through a five-year, $500,000 CAREEER Award from the National Science Foundation, a civil and environmental engineering research group at the University of Pittsburgh's Swanson School of Engineering will be developing new DNA sequencing methods to directly measure viral loads in water and better indicate potential threats to human health.
Jumping water striders know how to avoid breaking of the water surface
When escaping from attacking predators, different water strider species adjust their jump performance to their mass and morphology in order to jump off the water as fast and soon as possible without breaking of the water surface.
Water, water -- the two types of liquid water
There are two types of liquid water, according to research carried out by an international scientific collaboration.
Just add water? New MRI technique shows what drinking water does to your appetite, stomach and brain
Stomach MRI images combined with functional fMRI of the brain activity have provided scientists new insight into how the brain listens to the stomach during eating.
UM researchers found shallow-water corals are not related to their deep-water counterparts
A new study led by scientists at the University of Miami Rosenstiel School of Marine and Atmospheric Science found that shallow-reef corals are more closely related to their shallow-water counterparts over a thousand miles away than they are to deep-water corals on the same reef.
Saline water better than soap and water for cleaning wounds, researchers find
Researchers found that very low water pressure was an acceptable, low-cost alternative for washing out open fractures, and that the reoperation rate was higher in the group that used soap.
UTA research predicting lake levels, moving water to yield better data for water providers
A University of Texas at Arlington environmental engineer is creating an integrated decision support tool for optimal operation of water supply systems that will allow water providers to make better decisions about when to turn on pumps to transfer water from one reservoir system to another and when to release water downstream from the reservoirs.
Surfing water molecules could hold the key to fast and controllable water transport
Scientists at UCL have identified a new and potentially faster way of moving molecules across the surfaces of certain materials.

Related Water Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#532 A Class Conversation
This week we take a look at the sociology of class. What factors create and impact class? How do we try and study it? How does class play out differently in different countries like the US and the UK? How does it impact the political system? We talk with Daniel Laurison, Assistant Professor of Sociology at Swarthmore College and coauthor of the book "The Class Ceiling: Why it Pays to be Privileged", about class and its impacts on people and our systems.