Hou Xu
Is it possible to build a door with a flowing liquid?
Hou Xu, a young scholar at Xiamen University, did just that. This magical "door" is actually a kind of "liquid gating" membrane material that he originally created. Membrane materials in such as petrochemical, clean energy, sewage treatment, air purification, chemical testing and other fields have been widely used, and Hou Xu proposed the concept of "liquid gating", for energy saving, stability, low cost control and separation of various fluids provide a new idea, is expected to help achieve the overall improvement of the function and performance of traditional membrane materials.
Not long ago, with the above original innovation achievements and the excellent performance of social welfare science popularization work, Hou Xu won the honor of the second "National Innovation Scramble Award".
How did this post-80s scholar achieve this honor at a young age?
"Playing" with scientific research is one of his knacks. He believes: "Love of scientific research is one of the most important qualities of scientific researchers, and doing research must have a 'play' mentality." Only by liking your own research can you 'play' with interest and passion, and can you persistently deepen your research, otherwise it is difficult to achieve the ultimate. ”
After graduating from the Innovative Talents Class of Sichuan University, Hou Xu "played" all the way to the National Nanoscience Center and Harvard University. After the end of the Postdoctoral Work at Harvard, although he received an olive branch from a top foreign scientific research institution, he chose to return to China for development, joined Xiamen University, and formed a young bionic multi-scale aperture team to aim at the demand direction of core technologies in related fields of the country and carry out the research and development of intelligent new concept materials.
One of the team's most representative tasks is to propose and develop the concept of "reactive liquid gating" and lead this new direction internationally. Recently, he shared the team's latest research on icanx talks around the world.
Concept diagram of "responsive liquid gating" designed by Hou Xu's team. Courtesy of Hou Xu
Whether in the macro or micro world, "gating" plays an important role. The "doors" in the macroscopic world are usually solid, such as security doors and valves for water pipes. For example, the ion channels on the cell membrane in the human body that control nerve conduction can be regarded as a "gate" for ion transmission. Hou Xu's inspiration for using liquid molecules as "gates" comes from a structure in the biological alveoli - the Ku's hole.
Alveoli are fluid-filled tissues, and the Curface pores on the alveoli can elastically contract according to changes in surrounding pressure, forming an orifice that can be switched on and off. When the pressure is low, the liquid fills the pores and seals it, and when the pressure is high, the liquid sealing "door" opens quickly, and between the liquid "door" switches, the gas in the alveoli is released or blocked. Inspired by this, Hou Xu proposed the bionic concept of "liquid gating".
Why is it necessary to create a bionic liquid "door"? Hou Xu introduced that many scenes urgently need an extremely sealed, smooth and flat, stable and sensitive membrane material to do the "door", such as biomedical catheter membrane materials, intelligent agricultural greenhouse membranes, and even including heavy metal pollutants and drug rapid detection technology. His "liquid gating" can meet the demand, because the liquid has the unique advantage of being defect-free and achieving molecular level flatness, which makes its dynamic sealing and stain resistance far superior to existing solid materials.
Hou Xu introduced that in the microscopic world, it is difficult to avoid defects in large-area solid membrane materials. This means that it is difficult to 100% block the transmission of tiny substances in the gating of solid films. Gas molecules, for example, can easily pass through a nanoscale gap. In addition, the gap in the solid membrane material will cause the residue of the pathway material, and the accumulation of less into more, the membrane material will be polluted or even blocked, which is the pain point of the existing sewage treatment, air purification, and seawater purification membrane.
"The fluidity of the liquid can make the surface of the material reach molecular level flatness, and the liquid level is free of defects." This means that when the liquid 'door' is sealed, even the gas molecules cannot pass through; when the liquid 'door' is opened, the material that passes through can be unimpeded and free of residue. And because the "gate" made of liquid is very sensitive to the perception of pressure, its sensitivity is very high. In addition, in order to offset the disadvantage of liquid instability in the macroscopic state, Hou Xu cleverly chose a solid porous membrane material to act as a "door frame".
"Scientists need imagination." This is Hou Xu's experience in innovation. And his divergent thinking may also be related to "love to play".
Hou Xu is a big fan of various science fiction movies and "Man and Nature" and likes to draw inspiration from them. He is also an art lover and likes to learn from the perspective and way artists appreciate the world. In addition, as a "gluttonous" person, he is also particularly fond of cooking, good at making cold rabbit diced rabbits, pepper and ma chicken, boiled fish, back to the pot meat... What is more worth mentioning is that Hou Xu is very flexible in "playing", and it seems that he can integrate various ideas at any time.
At the same time, he also soberly realized that inspiration can fly, but the realization of inspiration must be inseparable from steadfastness, diligence and rigor. Hou Xu said: "Careful research, patience to loneliness, seeking truth from facts, perfectionism and heavenly rewards, never out of date." We should be grateful for the selfless dedication and teaching of many predecessors, who have laid a solid foundation and paved the way for us to build a world science and technology power. ”
In terms of personal growth trajectory, Hou Xu has also received many international recognitions, including being named one of the "Global Influential Young Scholars" in 2019 by the American Chemical Society's "Industrial and Engineering Chemistry Research", and being selected by the International Federation of Pure and Applied Chemistry as the No. 100 spokesperson for the periodic table of young chemists around the world... These honors made him more aware that personal gains are inseparable from the opportunities of the times, and that "only when the motherland is strong can individuals develop better."
"We are very fortunate to be able to contribute to the development of the country's scientific and technological undertakings today, when the national strength of the motherland is constantly strengthening." Hou Xu told reporters that in order to spur himself on, he recently wrote down a few mottos: "Micro-nano holes are hidden in the world, liquid gate control is clean, the development of science and technology for the people's livelihood, inheritance and struggle have my generation." (Zhang Qian)
Source: China Youth Daily