Cold welding of Metal-Organic Frameworks

1. National Science Foundation (Grant No. 1068952) (PI/L. Tan; Co-PI/X. Zeng). Cold welding of Metal-Organic Frameworks c b c Ziguang Chen1, Zhanping Xu, Jinyue Jiang1, Banglin Chen2, and Li Tan1* (ltan4@unl.edu) 1Department of Mechanical and Materials Engineering, University of Nebraska, Lincoln, NE, 68588, 2Department of Chemistry, UniVersity of Texas-Pan American, Edinburg, Texas 78541. a b Metal-Organic Framworks The weakest inter layer connection : (2 0 0) planes Heterogeneous structure • Metal Organic Frameworks (MOFs), a class of hybrid materials that combine organic ligands with metal atoms, is thought to have a bright future for various applications. Without CW B With CW C D Cold welding • No any changes revealed in XRD expect the full width at half maximum (FWHM). A Bold Idea: Powder Cold Welding: Micro scale ? Reality: Without CW With CW • Complex nanoparticle-assembly revealed on the surface. Surface Cold Welding: Nano scale • Sequential growth in real-time. Objectives • Monolayer growth limited by buckling. • Grain Size: From ~10 nm to ~30 nm • Young’s Modulus: From ~5 GPa to 13 GPa • Hardness: From ~400 MPa to 900 MPa • Manufacturing defects get self-repaired. • Understanding the heterogeneous structure of MOFs; • Explore the possibility of cold welding (CW); • Using cold welding to make a free-standing film; • After cold welding, the powder-assembly is elastic; • The free standing film is of similar yield strength as polycarbonate. Cu-MOF Conclusions • Heterogeneous feature is revealed in MOF crystals; • Cold welding is achieved with Cu-MOF ; • Cold welding makes application possibility of MOFs in engineering materials . (0 0 2) (0 2 2) (0 2 0) 100 mm 50 mm (2 0 0)