The connection between fundamental interactions acting in molecules in a fluid and macroscopically
measured properties, such as the viscosity between colloidal particles coated with polymers, is
studied here. The role that hydrodynamic and Brownian forces play in colloidal dispersions is also
discussed. It is argued that many-body systems in which all these interactions take place can be
accurately solved using computational simulation tools. One of those modern tools is the technique
known as dissipative particle dynamics, which incorporates Brownian and hydrodynamic forces, as well
as basic conservative interactions. A case study is reported, as an example of the applications of
this technique, which consists of the prediction of the viscosity and friction between two opposing
parallel surfaces covered with polymer chains, under the influence of a steady flow. This work is
intended to serve as an introduction to the subject of colloidal dispersions and computer
simulations, for…