Open cell aerogel foams with hierarchical pore structures

Publication date: 8 September 2017
Source:Polymer, Volume 125
Author(s): Senlong Gu, Sadhan C. Jana
A new class of macroscopic materials – the open cell aerogel foams (OCAFs) – are developed in this work that combine the attributes of open cell polymer foams and mesoporous polymer aerogels in single materials. The OCAFs have two functional elements – the large body of the materials is air-filled open cells with typical cell size greater than 1 μm and the walls between the open cells consisting of mesoporous aerogel formed by the polyurea strands of typical diameter 50 nm. The common foaming technologies cannot be easily adapted to obtain OCAF. This paper evaluates a strategy based on the use of templates of co-continuous immiscible polymer blends. The open cell macropores are created by selective dissolution of polystyrene from its co-continuous blend with polyethylene oxide. The gel networks of polyurea are then synthesized inside the macropores. Finally, the polyethylene oxide phase is removed by dissolution and the resultant material is dried under supercritical condition to obtain the OCAF. It is found that polyurea gel networks are initiated on the surfaces of polyethylene oxide template by nucleation and growth mechanism. The resultant polyurea OCAFs exhibit bulk density ∼0.06 g/cm³, BET surface area ∼130 m²/g, mesoporous solid networks, high air permeability, and close to 1500% weight gain in a few seconds when exposed to pump oil.

Graphical abstract

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