Polymer curing assisted formation of optically visible sub-micron blisters of multilayer graphene for local strain engineering.

The local or global straining techniques are used to modulate the electronic, vibrational and optical properties of the two-dimensional (2D) materials. However, manipulating the physical properties of a 2D material under a local strain is comparatively more challenging. In this work, we demonstrate an easy and efficient polymer curing assisted technique for the formation of optically visible multilayer graphene (MLG) blisters of different shapes and sizes. The detailed spectroscopic and morphological analyses have been employed for exploring the dynamics of the confined matter inside the sub-micron blisters, which confirms that the confined matter inside the blister is liquid (water). From further analyses, we find the nonlinear elastic plate model as an acceptable model under certain limits for the mechanical analyses of the MLG blisters over the (poly)vinyl alcohol (PVA) polymer film to estimate the MLG-substrate interfacial adhesion energy and confinement pressure inside the blisters. The findings open new pathways for exploiting the technique for the formation of sub-micron blisters of the 2D materials for local strain-engineering applications, as well as the temperature-controlled release of the confined matter.