(200e) Mechanically Stable Thermally Crosslinked Poly(acrylic acid)/ Reduced Graphene Oxide Aerogels

Porous carbonaceous materials, such as graphene-based aerogels (GAs), are very attractive because they possess a unique combination of properties including high surface area, excellent thermal and electrical conductivity, and low mass density (a few milligrams per cubic centimeter) compared to dense analogs. Such aerogels have a wide range of potential applications in energy storage devices, polymer composites, sensors, absorbents, catalysts, etc. However, one major drawback for GAs is that they are often very fragile, due to the weak Van der Waals interactions between adjacent two dimensional graphene sheets, resulting in a delicate structure. Numerous attempts to increase the mechanical properties of GAs have been made previously, such as introducing physically mixed additives like carbon nanotubes or incorporating short chemical crosslinks between graphene sheets. However, the previous additives or crosslinks used in GAs usually comprise a sizeable weight fraction of the final material, which often causes the collapse of the pore structure, or partially degrades some of the attractive properties of GAs.

We recently demonstrate a method [1] to enhance the mechanical properties of a specific type of GA composed of graphene oxide (GO) using a small amount of inexpensive, commercially available and thermally cross-linkable poly(acrylic acid) (PAA). Additionally, GO can be reduced to form reduced graphene oxide (rGO) in a single step using hydroiodic acid (HI) vapor. The thermally crosslinked graphene oxide aerogels (termed XPAA/rGO) exhibit dramatically improved mechanical properties, while all the other attractive features of GAs (high surface area, high porosity, high electrical conductivity, low density) are maintained. Finally, experiments revealing the performance of XPAA/rGO as superabsorbents, electrochemical energy storage electrodes and pressure sensors will also be discussed.

[1] Mechanically Stable Thermally Crosslinked Poly(Acrylic Acid)/Reduced Graphene Oxide Aerogels, H. Ha, K. Shanmuganathan, and C.J. Ellison⁺, ACS Applied Materials and Interfaces, 7, 6220–6229 (Feb. 2015).

http://pubs.acs.org/doi/abs/10.1021/acsami.5b00407