Early work focused on the mechanical properties of pristine SURMOF films [3,4]. In this study, we have investigated the influence of loading pristine highly oriented MOF films with TCNQ on the mechanical properties by utilizing nanoindentation methods to measure the hardness and modulus of SURMOF films with and without TCNQ loading. Our findings reveal that undoped pristine SURMOF samples are relatively harder with an intrinsic hardness of ~ 1.6 GPa in the upper third of the MOF film. The hardness of the pristine SURMOF samples is steadily increasing as a function of the penetration depth. The hardness is approaching the substrate Si hardness as the indenter tip approaches the substrate. The measured modulus values of the pristine SURMOF samples are also steadily increasing as a function of the indentation depth. However, the TCNQ loaded SURMOF samples differ markedly and do not show a substrate effect. Interestingly the loaded SURMOF films are much softer and exhibit a constant hardness as a function of depth of ~ 0.5 GPa. As the indenter approaches the Si substrate there is no measurable change in the constant hardness and an absence of a substrate effect. The modulus values of TCNQ loaded SURMOF films is also significantly lower compared with the pristine sample and remains constant as a function of indenter penetration depth. Thus, loading the porous scaffolding of SURMOF films with TCNQ did not only alter the electrical conductivity but triggers marked changes in the mechanical properties, i.e., softening effect. This softening effect in TCNQ infiltrated MOF films can be accounted for by a widening of the lattice constant und the concomitant introduction of lattice defects that weaken the crystal and lead to a much lower hardness.
 Xin Chen, Z. Wang, Zeinab M. Hassan, Pengtao Lin, Kai Zhang, H. Baumgart, E. Redel, ECS J. Solid State Sci. Technol. 6, (4), P150-P153 (2017)
 Z. Wang, D. Nminibapiel, P. Shrestha, J. Liu, W. Guo, P. Weidler, H. Baumgart, C. Wöll, E. Redel, ChemNanoMat, 2, (1), 67 (2016)
 S. Bundschuh, O. Kraft, H.K. Arslan, H. Glieman, P.G. Weidler, C. Wöll, Applied Phys. Letters, 101, 101910 (2012)
 J. P. Best, J. Michler, Jianxi Liu, Zhengbang Wang et al., Applied Physics Letters, 107, 101902 (2015)