promising method for large-area deposition of functional 2D material inks directly on to arbitrarily shaped objects. This is due to the ability of this technique to conform to the complex topographies of 3D objects. To date, such a method has not yet been developed for graphene and other 2D materials that is robust for large-area, single and multilayer devices for electronics and sensing.

Here, we introduce a method of conformal printing of a specifically formulated conductive graphene ink, exploiting the advantages of water-assisted conformal printing. This method first involves the formulation of a water-insoluble ink that can be printed *via* screen printing. For this, we use a combination of One Factor At A Time (OFAT) experiments (where we vary one factor in ink formulation and measure the corresponding outcome) and Design of Experiments (DOE), a method that we use to determine the inter-relationship between multiple components of the final ink formulation. OFAT experiments involve increasing the graphene loading until the ink is unprintable ($>$ 10 Pa s), while determining the minimum amount of binder required for the ink to be shear thinning during printing and to maintain its mechanical integrity on the substrate after curing. The results of OFAT are 