Graphene mass production is one of the key factors enabling the use of this material in electronic devices and sensors. The one of prospective methods of graphene fabrication is graphene grown on the metallic matrix from the liquid phase. In this paper we present Kelvin Probe Force Microscopy investigations of High Strength Metallurgical Graphene (HSMG) transferred on low-density polyethylene (LDPE) with patterned gold electrodes. The HSMG graphene was compared to the chemical vapor deposited graphene (CVD) also transferred on LDPE. We observed variations of contact potential difference (CPD) arising from the graphene-LDPE substrate interactions that influenced the electrical properties of graphene.