Mechanics of 2D Material Thin Films with Applications to Health and Nanofabrication TechnologiesdissertationsLi, DongcreatorGao, HuajianAdvisorKim, Kyung-SukReaderHurt, RobertReaderWei, LeiReaderBrown University. Engineering: Mechanics of Solidssponsor2021xviii, 120 p.born digitalThesis (Ph. D.)--Brown University, 2021thesesAbstract of Mechanics of 2D Material Thin Films with Applications to Health and Nanofabrication Technologies, by Dong Li, Ph.D., Brown University, May 2021. By virtue of the superior physical, mechanical and electronic properties, 2D material thin films in forms of monolayer, few layers and many layers have drawn great atten-tion to their various applications where mechanical behavior of these thin films plays significant roles. Here we investigate the mechanics of 2D material thin films in differ-ent systems and mechanical environments to help us evaluate mechanical properties of these films in extreme conditions and explore approaches to further improving their po-tentials in novel applications. We first study the interaction between graphene-based thin films and mosquito proboscis for developing 2D material barriers in mosquito bite prevention. The protective films under mosquito biting are modeled as freestanding membranes indented by a rigid tip. The modeling results show that reduced graphene oxide films thicker than 0.5 µm are capable to resist mosquito bite due to the mechani-cal barrier effect. Next, we investigate the shear failure of graphene oxide (GO) and MoSe2 multilayer thin films under lap shear loading. A cracked lap shear model with a pre-existing edge crack in the adhesive is proposed. Based on finite element results, we find that a shear-to-tensile failure mode transition as well as the different defect sizes in GO and MoSe2 is responsible for the distinct responses of the two 2D material thin films observed in experiment. Finally, we focus on a novel fabrication method of mi-croscopic particles based on classical cold drawing technique, which is potential in mass production of 2D material nanoribbons. For a brittle 2D nanosheet attached to a polymer material, we develop a necking-affected shear lag theory which predicts a peak tension in the nanosheet induced by a reverse shear lag zone. Sequential, controlled fragmentation is thus achieved to obtain large number of 2D material ribbons, with tun-able width through interfacial strength and geometrical dimensions. Overall, our studies provide theoretical insights on new applications and designs of 2D material thin films targeting protective coatings, wearable devices and advanced manufacturing.2D MaterialsSoil mechanicsEnglishRPB20211004In CopyrightAll rights reserved. Collection is open to the Brown community for research.