A method of making a hyperbranched amphiphilic polyester compound includes drying under vacuum a mixture of 2–malonic acid and p-toluene sulphonic acid as catalyst. A low-dimensional material chemical vapor sensor comprising monolayer flakes of MoS2, trenches in the SiO2Si wafer, metal contacts in the trenches, and thereby resulting in a MoS2 sensor. , a concrete wall, bridge, pillars, using a smart aggregate is disclosed. In one form the fuel additive can be mixed with a matrix material and released at a substantially constant rate to maintain a uniform level of fuel additive in the fuel.