Low-Cost Ambient Pressure Drying Approach for Highly Porous Nanomaterial Structures

Drying highly porous structures presents a fundamental challenge, as capillary forces during evaporation collapse pores, limiting utility. Despite advances in sol-gel processing and nanostructure synthesis, techniques such as critical point drying (CPD) drive up cost, limit size and reduce throughput. This creates a major bottleneck for scalable fabrication of aerogels, membranes, and advanced lightweight materials. Here, a simple, low-cost, solvent-based technique for ambient temperature and pressure drying of highly porous graphene, MXene, PEDOT:PSS, MoS₂, and TiO₂ structures is reported. The effectiveness of low surface tension solvents, hexamethyldisilizane and tetramethylsilane, are compared as drying media, while measurements of mass and volume during drying provide insight into the process. Using HMDS, capillary forces are minimized, and the microstructure of the materials is preserved. For example, shrinkage as low as 1.3% for graphene at an ultralow density of 0.018 g cm^-3 was achieved. TMS showed inferior drying performance in direct comparison to HMDS due to its high vapor pressure and rapid evaporation. The use of low surface tension solvents also allowed the creation of large 11 × 11 cm graphene structures, greatly exceeding the chamber size of typical CPD equipment. Finally, a comparison of the cost of ambient drying and CPD is presented.