la0c03312_si_001.pdf (1.38 MB)
Versatile Direct Writing of Aerogel-Based Sol–Gel Inks
journal contribution
posted on 2021-01-27, 17:55 authored by Jianming Yang, Hongqiang Wang, Bin Zhou, Jun Shen, Zhihua Zhang, Ai DuDirect
ink writing (DIW) of aerogels has great potential in designing
novel three-dimensional (3D) multifunctional materials with hierarchical
structures ranging from the nanoscale to the macroscopic scale. In
this paper, pure aerogels composed of inorganics, strongly cross-linking
organics, and weakly cross-linking organics were directly written
via the precise control of the gelation degree without using any additives.
The rheological properties of a resorcinol–formaldehyde aerogel-based
sol–gel ink (marked as RA ink) were measured at different reaction
times to determine the suitable printable range (G′LVR: several 103 Pa) that ensures its
good print fidelity. In addition, the rheological evolution of the
RA ink during the sol–gel process and under different shear
stresses was studied. The correlation of relevant parameters was established
according to the Hagen–Poiseuille model. Other typical aerogel-based
sol–gel inks including a silica aerogel-based sol–gel
ink (SA ink) and a polyimide aerogel-based sol–gel ink (PA
ink) for DIW were also demonstrated. Finally, water evaporation experiments
were carried out using a 3D-printed carbonized resorcinol–formaldehyde
aerogel (CA) to further exhibit the potential applications of this
novel technology in solar steam generation. The evaporation rate (1.57
kg m–2 h–1) and efficiency (88.38%)
of 3D-printed CA were higher than those of bulk CA (1.21 kg m–2 h–1 and 69.82%). This paper systematically
studies the control of DIW parameters for aerogel-based sol–gel
inks and shows a potential application in high-efficiency 3D-printed
evaporators.