Researchers at Pusan National University in South Korea have created innovative magnetic micropillar arrays made from disulfide-based covalent adaptable networks (DS-CANs) that can change, fix, and retain their shape reversibly using magnetic fields and ultraviolet (UV) light—at room temperature and without contact.

Magnetic micropillar arrays are tiny vertical structures arranged in a grid, made from flexible polymers embedded with magnetic particles. When exposed to a magnetic field, these micropillars shift to a pre-programmed shape and recover repeatedly without damage. However, conventional micropillar arrays only maintain their altered shape while the magnetic field is applied, limiting their practical use.

Addressing this limitation, the Pusan National University team developed DS-CANs—polymers with dynamic disulfide bonds that can break and reform when exposed to UV light or heat. This innovation enables on-demand, contactless shape fixation at room temperature, without the solvents or resins required by previous methods, making it energy efficient and precisely controllable.

“Our solvent- and resin-free shape fixation strategy overcomes major drawbacks of earlier approaches,” said Associate Professor Chae Bin Kim, lead researcher from the Department of Polymer Science and Engineering. “The ability to activate shape fixing with UV light at room temperature allows for non-contact, spatiotemporally precise processing, opening new possibilities for smart materials.”

What are shape-shifting smart polymers and why do they matter?

Shape-shifting smart polymers are materials that can change their shape in a controlled way when exposed to specific triggers, such as heat, light, or magnetic fields. This ability allows them to “remember” and fix a new shape temporarily or permanently, then revert back when triggered again.

The Pusan National University researchers developed polymers with dynamic disulfide bonds that can be activated by ultraviolet (UV) light at room temperature — a big step forward from previous materials that needed heat or solvents.

These materials have exciting potential in pharma and biotech because they enable:

• Smart drug delivery systems that can change shape to release medication precisely where and when needed

• Adaptive medical devices and surfaces that can conform to patient anatomy or environmental conditions

• Flexible manufacturing tools that simplify complex device fabrication and enable programmable microstructures

By combining magnetic responsiveness with UV-triggered shape fixation, these polymers allow non-contact, reversible, and highly precise control of shape — promising more efficient, customizable, and patient-friendly pharma technologies.

This technology also supports spatial control, allowing selective shape changes in specific areas via masked UV exposure. Additionally, the researchers demonstrated complex 3D microstructures by fabricating DS-CAN/NdFeB microdenticles—ribbed micropillars inspired by shark skin.

Dynamic disulfide bonds allow DS-CANs to repair damage, weld samples, and be reprocessed into solid materials, making them highly versatile. Molecular simulations helped the team understand the UV- and heat-triggered bond exchanges, guiding future material design.

Potential applications include tunable robotic grippers that conform to delicate shapes, programmable smart surfaces, switchable adhesives, and precisely controlled drug delivery systems.

“Our findings represent a significant leap in shape-changeable materials,” added Prof. Kim. “These UV-activated polymers pave the way for innovative microdevices with advanced, controllable capabilities.”

The study, featuring collaborators from Hanyang University and Dong-Eui University, was published in Advanced Materials (June 1, 2025) and selected as the front cover article for the journal’s July issue.