High-resolution 4D printing could hide anti-counterfeit information 22 Jan 2021 Professional Engineering In (a), the printed object's colour is clearly visible before it is compressed. After recovery, the colours are visible again. (b) shows the micron-scale object before, during and after compression (Credit: SUTD) Shape memory polymers have been ‘4D-printed’ at sub-micron dimensions, opening up potential applications including optical anti-counterfeiting. Researchers from the Singapore University of Technology and Design (SUTD) and collaborators developed the new technique, which is capable of high resolutions comparable to the wavelength of visible light. Applications could also include tuneable photonic devices. 4D printing is the 3D printing of objects that can change shape and transform in response to external stimuli. It is used in fields including soft robotics, flexible electronics and medical devices.