@article{liu_sui_harbinson_pudlo_perera_zhang_liu_ku_islam_liu_et al._2023, title={A scalable microstructure photonic coating fabricated by roll-to-roll “defects” for daytime sub-ambient passive radiative cooling}, volume={23}, ISSN={["1530-6992"]}, url={https://doi.org/10.1021/acs.nanolett.3c00111}, DOI={10.1021/acs.nanolett.3c00111}, abstractNote={The deep space's coldness (∼4 K) provides a ubiquitous and inexhaustible thermodynamic resource to suppress the cooling energy consumption. However, it is nontrivial to achieve subambient radiative cooling during daytime under strong direct sunlight, which requires rational and delicate photonic design for simultaneous high solar reflectivity (>94%) and thermal emissivity. A great challenge arises when trying to meet such strict photonic microstructure requirements while maintaining manufacturing scalability. Herein, we demonstrate a rapid, low-cost, template-free roll-to-roll method to fabricate spike microstructured photonic nanocomposite coatings with Al2O3 and TiO2 nanoparticles embedded that possess 96.0% of solar reflectivity and 97.0% of thermal emissivity. When facing direct sunlight in the spring of Chicago (average 699 W/m2 solar intensity), the coatings show a radiative cooling power of 39.1 W/m2. Combined with the coatings' superhydrophobic and contamination resistance merits, the potential 14.4% cooling energy-saving capability is numerically demonstrated across the United States.}, number={17}, journal={Nano Letters}, author={Liu, S. and Sui, C. and Harbinson, M. and Pudlo, M. and Perera, Himendra and Zhang, Zhenzhen and Liu, Ruguan and Ku, Zahyun and Islam, Md Didarul and Liu, Yuxuan and et al.}, editor={Ryu, JongEditor}, year={2023}, pages={7767–7774} }
 @article{lee_hong_jun_liu_ryu_kim_kim_lee_2023, title={Numerical and experimental studies on design of multi-lumen tube extruded with drawing and air flow}, volume={106}, ISSN={["2212-4616"]}, DOI={10.1016/j.jmapro.2023.09.074}, abstractNote={This study represents the design and optimization procedure of a multi-lumen tube used for endoscopic retrograde cholangiopancreatography (ERCP) catheter. The geometry of tip and die for the multi-lumen tube is designed based on numerical analysis of molten polymer and air flow. In particular, this numerical study consider the interaction between the molten polymer and the air flow in the lumen which is the main process variable of extrusion, and analyze the heat transfer and pressure distribution through the air flow for the first time. In addition, to reflect the reality of the multi-lumen extrusion process, the velocity is controlled at the end of the tube ejected to the free surface in consideration of the extrusion process, which is drawn by the puller downstream of the extruder. The shear rate and temperature dependent viscosity of PEBAX 7233 SA01 MED is measured for non-isothermal numerical simulations. The extrusion process for multi-lumen tubes with drawing is simulated using ANSYS Polyflow. The profile of extrudate is numerically predicted with the initial design of the tip and die with the manufacturing parameter is optimized. The predicted profile of extrudate is compared to the target profile with dimensional requirements. The design of the tip and die is modified based on numerical results following the design procedure. To suppress the die swell phenomena, the flow area of molten polymer is increased, and the velocity difference is reduced. Finally, the multi-lumen tube with the optimized tip and die is experimentally extruded and compared to the target profile of the extrudate. It has a good agreement with the target profile and satisfies the dimensional requirements. This design procedure and numerical analysis help achieve the desired target profile of extrudate.}, journal={JOURNAL OF MANUFACTURING PROCESSES}, author={Lee, Han Chang and Hong, Seong Geun and Jun, Wonjin and Liu, Sipan and Ryu, Jong Eun and Kim, Gyu Man and Kim, Woojin and Lee, Euntaek}, year={2023}, month={Nov}, pages={88–101} }
 @article{harbinson_pudlo_liu_chaudhry_liu_sui_zhu_hsu_ryu_2023, title={Template-free scalable roll-to-roll fabrication of textured transparent film for passive radiation cooling of photovoltaics}, volume={35}, ISSN={["2213-8463"]}, DOI={10.1016/j.mfglet.2023.08.006}, abstractNote={Solar panels contributed to over 115,000 GWh of energy being produced in the United States and solar panel energy consumption has increased by 27 % at the start of the 21st century. Given the decrease of photovoltaic efficiency at higher temperatures and the increasing demand for clean energy, the development of an economical technology for solar panel cooling is necessary. Passive cooling can be achieved by infrared radiating into space. Typical solar arrays require large functional areas in order to supply a significant amount of power as compared to other sources. As such, any method to help reduce the temperature of the solar panel surfaces needs to maintain manufacturing scalability for sustainable use. We demonstrate a rapid, low-cost, template-free roll coating method to fabricate photonic composite film with SiO2 nanoparticles which possess high emissivity in the atmospheric transparent window while passing visible and near infrared light to photovoltaics beneath. When facing direct sunlight at summer noon, the coatings show a 3.5°C temperature decrease without loss of photovoltaic efficiency while having hydrophobic and contamination-resistance merits.}, journal={MANUFACTURING LETTERS}, author={Harbinson, Myers and Pudlo, Michael and Liu, Sipan and Chaudhry, Taimur and Liu, Yuxuan and Sui, Chenxi and Zhu, Yong and Hsu, Po-Chun and Ryu, Jong E.}, year={2023}, month={Aug}, pages={166–173} }
 @article{black_chockalingam_islam_liu_perera_khan_ryu_2022, title={Fabrication of Bioinspired Micro/Nano-Textured Surfaces Through Scalable Roll Coating Manufacturing}, volume={10}, ISSN={2166-0468 2166-0476}, url={http://dx.doi.org/10.1115/1.4056732}, DOI={10.1115/1.4056732}, abstractNote={Abstract}, number={2}, journal={Journal of Micro and Nano-Manufacturing}, publisher={ASME International}, author={Black, Benjamin and Chockalingam, Sekkappan and Islam, Md Didarul and Liu, Sipan and Perera, Himendra and Khan, Saad and Ryu, Jong Eun}, year={2022}, month={Jun}, pages={021006} }
 @article{liu_kim_huang_chang_jiang_ryu_2022, title={Multiscale and multiphysics FEA simulation and materials optimization for laser ultrasound transducers}, volume={31}, ISSN={["2352-4928"]}, url={http://dx.doi.org/10.1016/j.mtcomm.2022.103599}, DOI={10.1016/j.mtcomm.2022.103599}, abstractNote={The relationship between the nanocomposite design and the laser ultrasound transducer (LUT) characteristics was investigated through simulations in multiple scale levels for material behavior, device response, and acoustic wave propagation in media. First, the effects of the nanoparticle size and concentration on the effective properties of composites were quantitatively investigated with the finite element analysis (FEA) method. Second, the effective properties of the nanocomposite were assigned to the layer, which is modeled as a homogeneous material, in the FEA for the LUT simulating the energy conversion from the incident laser to the acoustic wave. Finally, the ultrasound propagation in the water was calculated by a theoretical wave propagation model. The FEA-based prediction was compared with the experimental data in the literature and a theoretical analysis for LUT based on Thermal-Acoustic coupling. As a result, the ultrasound waves on the transducer surface and at a distance in the water could be predicted. Based on the hierarchically integrated prediction procedure, the optimal conditions of the photoacoustic nanocomposites were investigated through the parametric study with the particle size and concentration as variables. The results guide the material designs optimized for different device characteristics, such as high pressure and broad bandwidth.}, journal={MATERIALS TODAY COMMUNICATIONS}, publisher={Elsevier BV}, author={Liu, Sipan and Kim, Howuk and Huang, Wenbin and Chang, Wei-Yi and Jiang, Xiaoning and Ryu, Jong Eun}, year={2022}, month={Jun} }
 @article{islam_liu_choi_guo_ryu_2022, title={Physics-based Computational Method Predicting the Dielectric Properties of Polymer Nanocomposites}, volume={4}, ISSN={["1573-4897"]}, url={http://dx.doi.org/10.1007/s10443-022-10026-3}, DOI={10.1007/s10443-022-10026-3}, number={4}, journal={APPLIED COMPOSITE MATERIALS}, publisher={Springer Science and Business Media LLC}, author={Islam, Md Didarul and Liu, Sipan and Choi, Daniel and Guo, Zhanhu and Ryu, Jong Eun}, year={2022}, month={Apr} }
 @article{liu_islam_ku_boyd_zhong_urbas_smith_derov_nguyen_kim_et al._2021, title={Novel computational design of high refractive index nanocomposites and effective refractive index tuning based on nanoparticle morphology effect}, volume={223}, ISSN={["1879-1069"]}, url={https://doi.org/10.1016/j.compositesb.2021.109128}, DOI={10.1016/j.compositesb.2021.109128}, abstractNote={This study introduces a method to predict the refractive index (RI) of nanocomposites with the Finite Elements Analysis (FEA) based on the Fabry-Pérot interference. The efficacy was verified by comparing the estimated composites’ RI with the available data in the literature. In the experimental verification, the FEA-based prediction showed closer results with the measurement as compared to the effective medium approximation (EMA) approaches, which are prevalently used to predict the physical properties of nanocomposites. Due to the modeling capability, the FEA-method could investigate the effect of the nanoparticle morphology (particle size, shape, and orientation) and distribution. Large particle size, particle agglomeration in high electric-field amplitude region, and particle elongation along the light oscillating direction are found to be the major factors to enhance the RI of composites. The underlying mechanism of RI changing is attributed to the light scattering by embedded nanoparticles, which provides one potential real-time RI tuning schematic.}, journal={COMPOSITES PART B-ENGINEERING}, publisher={Elsevier BV}, author={Liu, Sipan and Islam, Md Didarul and Ku, Zahyun and Boyd, Darryl A. and Zhong, Yaxu and Urbas, Augustine M. and Smith, Evan and Derov, John and Nguyen, Vinh Q. and Kim, Woohong and et al.}, year={2021}, month={Oct} }
 @article{liu_islam_ku_urbas_boyd_kim_sanghera_ryu_2021, title={The polymer nanocomposites embedded particles size and agglomeration effect on the effective refractive index tuning}, volume={11802}, ISSN={["1996-756X"]}, url={http://dx.doi.org/10.1117/12.2594382}, DOI={10.1117/12.2594382}, abstractNote={The polymer nanocomposites have attracted increasing attention in the optical components that are miniaturized and integrated with wearable or portable electronics due to the polymer processibility and the tunability of the refractive index (RI) by adding nanoparticles. However, the lack of models predicting the composites’ RI attributed to the morphology, physical properties, as well as volume fraction of the nanoparticles poses difficulties in the design. This study investigates the effect of the size and agglomeration condition of the nanoparticles on the effective RI based on a Finite Element Analysis (FEA) method simulating the Fabry-Pérot resonance within the composite film. The result showed that larger particles (or particle clusters) could reinforce the RI of nanocomposites compared with the well-dispersed small particles. The particle-cluster model had lower RI than the single-solid-particle model with the same effective particle diameter, demonstrating that the particle cluster provides less scattering intensity than the single-solid-particle.}, journal={NANOENGINEERING: FABRICATION, PROPERTIES, OPTICS, THIN FILMS, AND DEVICES XVIII}, publisher={SPIE}, author={Liu, Sipan and Islam, Md Didarul and Ku, Zahyun and Urbas, Augustine M. and Boyd, Darryl A. and Kim, Woohong and Sanghera, Jasbinder S. and Ryu, Jong E.}, editor={Park, Wounjhang and Attias, André-Jean and Panchapakesan, BalajiEditors}, year={2021} }