Abstract
The speaker describes a simple approach to fold polymer sheets in a hands-free manner that users localized light absorption on a pre-stressed polymer film to induce self-folding. Self-folding is a deterministic ‘origami’ process, based on the ancient Japanese art of paper folding, that causes a predefined 2D template to fold into a desired 3D structure with high fidelity. Self-folding takes advantage of the multitude of available 2D patterning techniques (e.g. lithography, inkjet printing, screen printing). Self-folding is attractive as a cost-effective 3D fabrication strategy for applications such as packaging, robotic actuators and sensors, biological devices, solar cells, and reconfigurable devices. Most approaches to self-folding use hinges (i.e. regions of a substrate that fold) that have unique chemical composition from the bulk, which requires complicated photolithography or other multiple fabrication steps. Here the speaker will demonstrate a simple method for self-folding of polymer sheets utilizing localized light absorption on selected areas of the pre-strained polymer sheet. The ink is patterned via a desktop printer and it defines the location of the ‘hinge’ on the sheet. The inked areas on the 2D sheet absorb light preferentially, thus causing the polymer sheet to fold locally in the inked regions. The temperature gradients through the depth of the sheet induce localized shrinkage and the sheet folds within seconds. This patterned polymer sheets act as shape memory materials which can be programmed to fold into various 3D structures based on the nature of the light source, the shape and size of the ink patterns, and ink color. By controlling the aforementioned parameters, a complete control of the time and degree of folding, which ultimately govern the final 3D shape of the folded object can be achieved. This approach is appealing because it uses inexpensive materials and simple patterning techniques to form complex structures.
About the speaker
Prof Jan Genzer received his Diplom-Engineer in Materials and Chemical Engineering from Prague Institute of Chemical Technology in 1989 and PhD in Materials Science and Engineering from the University of Pennsylvania in 1995. He then became a Post-Doctoral Research Associate at Cornell University and University of California at Santa Barbara. In 1998, he joined North Carolina State University as an Assistant Professor of Chemical Engineering. He is currently the S. Frank & Doris Culberson Distinguished Professor and Associate Department Head in the Department of Chemical & Biomolecular Engineering at NC State University.
Prof Genzer is a highly recognized scholar and teacher. His honors and awards include the Camille Dreyfus Teacher-Scholar Award, NSF CAREER award, John H. Dillon Award of the American Physical Society, NSF Award for Special Creativity, NC State's Outstanding Teacher Award, NC State’s Alumni Outstanding Research Award, NC State’s Alcoa Foundation Distinguished Engineering Research Award, NC State’s Alumni Distinguished Undergraduate Professor award, NC ACS Outstanding Lecturer Award, and others. He is a Fellow of the American Physical Society. Prof Genzer published more than 220 peer-reviewed journal articles and delivered more than 190 invited lectures.
Currently, Prof Genzer’s group is involved in research related to the behavior of polymers at surfaces, interfaces and in confined geometries, with particular emphasis on self-assembly and forced assembly, and combinatorial methods. He is the co-director of the Research Triangle Materials Research Science & Engineering Center (RT-MRSEC).
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