Nanocorrugation of thin polymeric membranes to enhance CO2 capture and to reduce its emissions

The emission of carbon dioxide (CO2) is one of the serious environmental problems and has been recognized as the main contributor to global warming and climate change [1]. The Transnational Paris Agreement signed in 2016 set the goal for governments to limit the further emission of CO2 into the atmosphere in order to reduce interference with Earth’s climate system, which is essential for sustainable food production and economic development [2]. The emission of CO2 can be reduced through several ways and its separation by polymeric membranes is considered one of the promising options for its capture. However, this technique suffers of a low throughput and the challenge is make selective layer very thin to achieve high flux. [3] Nanotechnology efforts are focused on reducing the thickness of the membrane to be as thin as possible (<50 nm). Nano constrain on selective layers can produce different macromolecular conformations and crystallization processes such that to obtain exceptional results in terms of permeance and selectivity. Unfortunately, these researches are still far from technology transfer because of low reliability. Our studies on CO2 permeability of PDMS membranes with thickness ranging from 200 nm to 100 µm have revealed a thickness dependence of the gas flux on the thickness. This phenomenon is related to Non-Equilibrium Conditions (NEC) at the membrane surfaces, and is valid for any couple of gas/polymer [4]. Taking into account this drawback we have developed PDMS membranes with nano corrugated surfaces. The results show that for thicknesses such that NEC limits the gas flux, the roughness increases the permeance and have effects also on the selectivity [5]. This simple modification allows to enhance the gas throughput and it is cost effective because of its easily of fabrication.