Lowe Alexander R, Chora Żewski Mirosław A, Grosu Yaroslav, Bushuev Yuriy G
Institute of Chemistry, University of Silesia in Katowice, 40-006 Katowice, Poland.
Centre for Cooperative Research on Alternative Energies (CIC EnergiGUNE), Basque Research and Technology Alliance (BRTA), Vitoria-Gasteiz 01510, Spain.
J Phys Chem Lett. 2024 Dec 12;15(49):12112-12119. doi: 10.1021/acs.jpclett.4c02581. Epub 2024 Nov 27.
A new propulsion mechanism for nano- and microrocket engines is hypothesized. It is based on the instantaneous expulsion from hydrophobic nanopores triggered by irradiation from electromagnetic microwaves, ultrasound, or sudden pressure release. A large energy output is needed for the propulsion of a nanoparticle, and the value can be determined experimentally and by means of atomistic simulations. As such, we measured the heat of intrusion of water into ITQ-29 (LTA) pure silica zeolite with cage structure of pores. The heat effect is exothermic and equal to -7.3 ± 0.8 J/g of zeolite. Similar values were reported for chabazite, ZIF-8, and grafted mesoporous silica EVA. All these materials have cage structures of pores. In contrast, silicalite-1 (MFI) zeolite with a channel structure of pores exhibits endothermic intrusion. Molecular dynamics simulations of pure silica zeolites with LTA, CHA, and MFI topologies at a broad range of water loadings show that water becomes thermodynamically stable in cage-shaped pores while it is unstable in channel-shaped pores. A large energy release is expected during water expulsion from channel-type pores.
一种用于纳米和微型火箭发动机的新型推进机制被提出假设。它基于由电磁微波、超声波照射或突然的压力释放触发的从疏水纳米孔中的瞬间排出。推进纳米粒子需要大量的能量输出，该值可以通过实验和原子模拟来确定。因此，我们测量了水侵入具有笼状孔结构的ITQ-29（LTA）纯硅沸石的热效应。热效应是放热的，等于-7.3±0.8 J/g沸石。对于菱沸石、ZIF-8和接枝介孔二氧化硅EVA也报道了类似的值。所有这些材料都具有笼状孔结构。相比之下，具有通道状孔结构的硅沸石-1（MFI）沸石表现出吸热侵入。在广泛的水负载量下对具有LTA、CHA和MFI拓扑结构的纯硅沸石进行分子动力学模拟表明，水在笼状孔中是热力学稳定的，而在通道状孔中是不稳定的。预计在水从通道型孔中排出时会有大量能量释放。
