BLISTER ADHESION MEASUREMENTS OF LARGE AREA GRAPHENE
Kenneth Liechti (), Zhiyi Cao (), Peng Wang (UT Austin), Rui Huang (University of Texas at Austin)
Mechanics of Thin Films and Multilayered Structures
Tue 9:00 - 10:30
Salomon 203
Experimental techniques that are capable of characterizing the interfacial adhesion between graphene and various substrate materials (e.g., Si/SiO2, metals, polymers and elastomers) are needed along with theoretical models that enable fundamental understanding and engineering design of the interfaces. The objective of this work is to explore the use of blister testing with associated analysis for such purposes. The paper describes the development of a meso scale blister for determining the adhesion of graphene that, in this case, had been transferred to a highly polished copper substrate from its seed foil. The graphene was transferred with a photoresist backing to the copper, covering a nominally 1 mm diameter hole. The graphene/photoresist composite layer was pressurized with deionized water whose volume injection rate was controlled by a syringe pump. The pressure and deflection of the layer were measured respectively by a pressure transducer and an optical interference objective in a microscope. The resulting fringe patterns were image-processed in order to obtain the deflection of the top surface of the photoresist. The deflection profiles were compared with those obtained from nonlinear plate analyses that accounted for the initial strain in the film and a foundation stiffness that essentially accounted for relaxed encastré condition at the edge of the blister. Once the deflection profiles were reconciled, resistance curves were extracted from the analysis for graphene/copper and photoresist/copper interfaces. Interesting differences in adhesion have been discovered and are the subject of ongoing study.