@article{ma_vaghani_im_kong_shamsi_wei_vong_dickey_2024, title={Injection Molding of Liquid Metal by Harnessing Nonstick Molds}, volume={2}, ISSN={["1944-8252"]}, url={https://doi.org/10.1021/acsami.3c16692}, DOI={10.1021/acsami.3c16692}, abstractNote={The fluid nature of liquid metals combined with their ability to form a solid native oxide skin enables them to be patterned in ways that would be challenging for solid metals. The present work shows a unique way of patterning liquid metals by injecting liquid metals into a mold. The mold contains a nonstick coating that enables the removal of the mold, thereby leaving just the liquid metal on the target substrate. This approach offers the simplicity and structural control of molding but without having the mold become part of the device. Thus, the metal can be encapsulated with very soft polymers that collapse if used as microchannels. The same mold can be used multiple times for high-volume patterning of liquid metal. The injection molding method is rapid and reliably produces structures with complex geometries on both flat and curved surfaces. We demonstrate the method by fabricating an elastomeric Joule heater and an electroadhesive soft gripper to show the potential of the method for soft and stretchable devices.}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Ma, Jinwoo and Vaghani, Dhwanil P. and Im, Sooik and Kong, Minsik and Shamsi, Mohammad and Wei, Shuzhen and Vong, Man Hou and Dickey, Michael D.}, year={2024}, month={Feb} }
 @article{krisnadi_kim_im_chacko_vong_rykaczewski_park_dickey_2024, title={Printable Liquid Metal Foams That Grow When Watered}, volume={1}, ISSN={["1521-4095"]}, url={https://doi.org/10.1002/adma.202308862}, DOI={10.1002/adma.202308862}, abstractNote={Abstract}, journal={ADVANCED MATERIALS}, author={Krisnadi, Febby and Kim, Seoyeon and Im, Sooik and Chacko, Dennis and Vong, Man Hou and Rykaczewski, Konrad and Park, Sungjune and Dickey, Michael D.}, year={2024}, month={Jan} }
 @article{shen_jiang_wang_song_vong_jung_krisnadi_kan_zheng_fu_et al._2023, title={Liquid metal-based soft, hermetic, and wireless-communicable seals for stretchable systems}, volume={379}, ISSN={["1095-9203"]}, url={https://doi.org/10.1126/science.ade7341}, DOI={10.1126/science.ade7341}, abstractNote={Soft materials tend to be highly permeable to gases, making it difficult to create stretchable hermetic seals. With the integration of spacers, we demonstrate the use of liquid metals, which show both metallic and fluidic properties, as stretchable hermetic seals. Such soft seals are used in both a stretchable battery and a stretchable heat transfer system that involve volatile fluids, including water and organic fluids. The capacity retention of the battery was ~72.5% after 500 cycles, and the sealed heat transfer system showed an increased thermal conductivity of approximately 309 watts per meter-kelvin while strained and heated. Furthermore, with the incorporation of a signal transmission window, we demonstrated wireless communication through such seals. This work provides a route to create stretchable yet hermetic packaging design solutions for soft devices.}, number={6631}, journal={SCIENCE}, author={Shen, Qingchen and Jiang, Modi and Wang, Ruitong and Song, Kexian and Vong, Man Hou and Jung, Woojin and Krisnadi, Febby and Kan, Ruyu and Zheng, Feiyu and Fu, Benwei and et al.}, year={2023}, month={Feb}, pages={488–493} }
 @article{ma_krisnadi_vong_kong_awartani_dickey_2023, title={Shaping a Soft Future: Patterning Liquid Metals}, volume={3}, ISSN={["1521-4095"]}, url={https://doi.org/10.1002/adma.202205196}, DOI={10.1002/adma.202205196}, abstractNote={Abstract}, journal={ADVANCED MATERIALS}, author={Ma, Jinwoo and Krisnadi, Febby and Vong, Man Hou and Kong, Minsik and Awartani, Omar M. and Dickey, Michael D.}, year={2023}, month={Mar} }
 @article{joshipura_persson_oh_kong_vong_ni_alsafatwi_parekh_zhao_dickey_2021, title={Are Contact Angle Measurements Useful for Oxide-Coated Liquid Metals?}, volume={37}, ISSN={["0743-7463"]}, DOI={10.1021/acs.langmuir.1c01173}, abstractNote={This work establishes that static contact angles for gallium-based liquid metals have no utility despite the continued and common use of such angles in the literature. In the presence of oxygen, these metals rapidly form a thin (∼1-3 nm) surface oxide "skin" that adheres to many surfaces and mechanically impedes its flow. This property is problematic for contact angle measurements, which presume the ability of liquids to flow freely to adopt shapes that minimize the interfacial energy. We show here that advancing angles for a metal are always high (>140°)-even on substrates to which it adheres-because the solid native oxide must rupture in tension to advance the contact line. The advancing angle for the metal depends subtly on the substrate surface chemistry but does not vary strongly with hydrophobicity of the substrate. During receding measurements, the metal droplet initially sags as the liquid withdraws from the "sac" formed by the skin and thus the contact area with the substrate initially increases despite its volumetric recession. The oxide pins at the perimeter of the deflated "sac" on all the surfaces are tested, except for certain rough surfaces. With additional withdrawal of the liquid metal, the pinned angle gets smaller until eventually the oxide "sac" collapses. Thus, static contact angles can be manipulated mechanically from 0° to >140° due to hysteresis and are therefore uninformative. We also provide recommendations and best practices for wetting experiments, which may find use in applications that use these alloys such as soft electronics, composites, and microfluidics.}, number={37}, journal={LANGMUIR}, author={Joshipura, Ishan D. and Persson, K. Alex and Oh, Ji-Hyun and Kong, Minsik and Vong, Man Hou and Ni, Chujun and Alsafatwi, Mohanad and Parekh, Dishit P. and Zhao, Hong and Dickey, Michael D.}, year={2021}, month={Sep}, pages={10914–10923} }