Researchers at Dartmouth College have recently achieved a remarkable breakthrough with the development of a new 3D printing material. This innovative ”smart ink” will allow for the 3D printing of dynamic objects that change shape and color over time. This process offers a relatively straightforward and affordable version of what is often referred to as 4D printing, the next generation of additive manufacturing, and it could prove to have all kinds of applications in areas such as biomedicine and the energy industry.
(credit: Chenfeng Ke)
“This technique gives life to 3D-printed objects,” said Chenfeng Ke, an assistant professor of Chemistry at Dartmouth. “While many 3D-printed structures are just shapes that don’t reflect the molecular properties of the material, these inks bring functional molecules to the 3D printing world. We can now print smart objects for a variety of uses.”
The pioneering project sought to find a way of offering higher levels of control over the molecular structure of 3D printed objects. The advantages of this are huge, with design capabilities expanding greatly.
The ink was created by using a polymer-based “vehicle”, which can integrate intelligent molecular systems into printing gel. This allows for the transformation of their functions from the nano-scale to the macro-scale. Instead of hardening after 3D printing, the material undergoes further chemical reactions which lock active molecular ingredients together and set off transformations. With the intergration of fluorescent trackers, for example, the objects can be made to change color in response to an external stimulus such as light.
Another example of the kinds of changes that these 3D printed ”4D” objects can undergo is the repeated expansion and contraction in size through the use of supramolecular pillars. This contraction could be used to reduce the size of a 3D printed object by up to 100 times, offering 10 times the resolution. This means that the use of the Dartmouth team’s ink would expand the capabilities of a regular printer to the level of a much more sophisticated one, allowing it to print in a higher resolution without any changes to its operation, as the ink pre-programs the transformational capabilities into the object.
(source: Toner Giant)
“This process can use a $1,000 printer to print what used to require a $100,000 printer,” said Ke. “This technique is scalable, widely adaptable and can dramatically reduce costs.”
While full-blown intelligent 3D systems that can dynamically adapt to their environment and change their configuration are still some way off, the development of this new smart ink definitely has some potential uses already. The manufacturing of improved precision filters and storage devices is currently envisaged as something that would benefit from the ability to control structure and precisely plan the transformation of an object after printing.
The team summarised the project and its future potential, stating that, “We believe this new approach will initiate the development of small molecule-based 3D printing materials and greatly accelerate the development of smart materials and devices beyond our current grasp that are capable of doing complex tasks in response to environmental stimuli.”
Longyu Li, Pengfei Zhang, Zhiyun Zhang, Qianming Lin, Yuyang Wu, Alexander Cheng, Yunxiao Lin, Christina M. Thompson, Ronald A. Smaldone, Chenfeng Ke. Hierarchical Co-Assembly Enhanced Direct Ink Writing. Angewandte Chemie International Edition, 2018; DOI: 10.1002/anie.201800593