It is now possible to create angstrom-scale channels that can be viewed as if one or a few atomic planes are pulled out of a bulk crystal leaving behind a two-dimensional space. I shall overview our recent work on this subject, which covers the properties of gases, liquids and ions under the extreme confinement.

In recent years, experiments from different groups have reported that evaporation under sunlight from hydrogels and other porous materials can exceed the thermal evaporation limit by several times, i.e., super-thermal. We hypothesize that photons can directly cleave off water clusters at the liquid-vapor interface in a way similar to the photoelectric effect, which we call the photomolecular effect. We carried out over 20 different experiments on both hydrogel and a water-air interface to demonstrate this effect. Some key experiments include: (1) partially wet hydrogels become absorbing despite their constituent materials are transparent; (2) super-thermal evaporation; (3) polarization, angle-of-incidence, and wavelength dependences of optical responses at a single air-water interface to visible-light where bulk water does not absorb; (4) cooling of air under visible light irradiation; and (5) Raman and IR signatures of water clusters in the air. We also demonstrate that visible light heats up a thin layer of fog, with temperature rise peaking at the green wavelength where water is least absorbing. Our work could resolve an 80-year puzzle in atmospheric science: experiments reported more cloud absorption than theory could predicts. Progress in theoretical description of the photomolecular effect will also be summarized. Our study suggests that the photomolecular effect should happen widely in nature, from clouds to fogs, ocean to soil surfaces, and plant transpiration, and can also lead to new applications in energy and clear water.

A fundamental challenge of modern physical science is to form structure that is not frozen in place but instead reconfigures internally driven by energy throughput and adapts to its environment robustly. With catalytic enzymes, we find problems of mechanobiology. With chemical reactions, we find problems of active matter. Exploring the potential of liquid-phase TEM to image individual molecules and their mutual interactions, we analyze failed and successful encounters of polymers and proteins, and visualize enzyme conformational changes in real time. A picture emerges in which simple experiments, performed at single-particle and single-molecule resolution, can dissect macroscopic phenomena in ways that surprise.

Since the beginning of this century, the development trend of information technology to intelligent technology is increasing, the sustainable development problems, such as climate, green energy and how to understand human brain, become increasingly urgent. This trend makes scientists face the challenge of multi-phase media, multi-scale strong nonlinear coupling, especially the force-electric-magnetic-light-thermal coupling at the solid-liquid interface. We will review the recent advances in hydrovoltaics for harvesting environmental energy, serving as a potential Negative thermal emission energy technology, and briefly discuss the role of confined water in our brain and envision the hydrovoltaic intelligence.

Life system presents an ultralow energy consumption in high-efficiency energy conversion, information transmission and bio-synthesis. The total energy intake of human body is about 2000 kcal/day to maintain all our activities, which is comparable to a power of ~ 100 W. The energy required for brain to work is equivalent to ~ 20 W, while the rest energy (~ 80 W) is used for other activities. All in vivo bio-syntheses take place only at body temperature, which is much lower than that of in vitro reactions. To achieve these ultralow energy-consumption processes, there should be a kind of ultralow-resistivity matter transport in nanochannels (e.g., ionic, molecular channels), in which the directional collective motion of ions or molecules is a necessary condition, rather than the traditional Newton diffusion. Directional collective motion of ions and molecules are considered as ionic/molecular superfluid. The research of ionic/molecular superfluid will promote the development of neuroscience and brain science, develop quantum ionic technology, construct future chemical reactors with high flux, high selectivity and low energy consumption, and produce a series of disruptive technologies.