Molecular modelling of polymer-based membrane processes

The positive aspects of the increase in the standards of the quality of life have as drawback aspects the occurrence of related problems such as water stress, the environmental pollution, and the increase of CO2 emissions into the atmosphere. Membrane technologies have been gradually used for a wide range of applications, including the production of potable water, energy generation, tissue repair, pharmaceutical production, food packaging and the separations needed for the manufacture of chemicals, and have provided feasible alternatives for more traditional purification and separation processes. The core of every membrane process rely on a nanostructured/functionalised thin interface that controls the exchange between two phases due to external forces, under the effect of fluid properties, and based on the intrinsic characteristics of the membrane material [?1]. In order to develop advanced membrane technologies, a good understanding of the materials properties and their transport mechanisms, as well as the realization of innovative functional materials with improved properties, are key issues. In the effort to develop next generation membranes with enhanced performances, much attentions has been put in the new membrane material and membrane architecture. Amorphous polymers or nanostructured composites with inorganic components are an important class of materials to solve many of the above mentioned problems. However, the design of these multifunctional materials, based on experimentation and correlative thinking alone is unreliable, time consuming, expensive and often not successful. Systematic multi scale computer-aided molecular design offers a very attractive alternative. These techniques allow for the very elaborate investigation of complex material behaviour with regard to the links between structure, dynamics and relevant properties, which are most important for the penetrant transport and other relevant processes (e.g. selective transport, separation, catalysis, biodegradation, sensor applications) of interest. During the last decades, computational chemistry had a favourable impact in almost all branches of materials research ranging from phase determination to structural characterization and property prediction [?2, ?3, ?4, ?5, ?6, ?7], as it allows dealing with different types of polymers as well as, for example, with thermal conductivity of composites [?8], advanced batteries [?9, ?10], etc... Moreover, molecular simulations have reached an incredible development in the field of membrane science in the recent years, addressing both the membrane material itself and the transport and sorption phenomena. [?11, ?12, ?13, ?14, ?15, ?16]. Today, molecular dynamics simulations can be considered as a chemical engineering tool being part of the "molecular Processes-Product-Process (3PE)" integrated multiscale approach [?17]. In the present chapter atomistic modelling tools will be in the focus of interest, more specifically, molecular dynamics simulations