Strength and Flexibility – Prof. Shan Shi’s Work with Nanoporous Metals

,Metallic muscles’ might bring to mind heavy, clumsy robots, but not for Professor Shan Shi, leader of the Integrated Metallic Nanomaterials Group at Hamburg University of Technology. At the nanoscale, she says, porous metals can be remarkably responsive and therefore have strong potential for their use in soft robotics — a field traditionally dominated by polymers rather than metals. While polymers offer flexibility, they often lack mechanical strength. Nanoporous metals, by contrast, combine deformability with higher strength and durability, opening new possibilities for actuators that mimic the motion of natural muscles while benefiting from metallic robustness.

Four years ago, in April 2022, Shi began her position as Tenure-track Junior Professor at TUHH. After completing PhD and PostDoc at Helmholtz Center Hereon and TUHH, she received an offer from Tsinghua University in her home country China, but chose to continue her career in Germany. “It was the perfect fit for my own interests,” she says, as it allowed her to pursue research topics she is most passionate about and work alongside scientists like Prof. Jörg Weißmüller, whom she greatly admires.

Co-Leader in Cluster of Excellence

Shan Shi is not only interim Head of the Institute of Materials Physics and Technology at TUHH, but also co-leading the research area ,Mechanical Materials’ within the Cluster of Excellence BlueMat from the very beginning of the application phase. BlueMat aims to develop nature-inspired, sustainable, and interactive material systems that unfold their unique functionality in water or aqueous environments. Together with Prof. Norbert Huber and the team Prof. Shi is working on developing wetted nanoporous metals with autonomous sensing, shape-changing abilities, and switchable acoustic transmission. Through turning electrical signals into mechanical movement she and her research team are creating new actuators, called metallic muscles.

Enjoying Experiments

She has not chosen an easy subject, Shi admits: To create monolithic, robust and crack free nanoporous metals demands elaborate and time-consuming testing of many parameters, which is very challenging. But Shi is experienced with dry spells and says: „I strongly believe: You should love it and be happy when you are experimenting. If you feel no hope, the experiment won´t work.“ She remembers that during her PhD an important experiment did not work out for several months, but then she went on holiday, came back completely relaxed and suddenly was successful.

Motherhood in Science 

Meanwhile Shi is not experimenting in the laboratory as much as she used to, but enjoys supervising her seven PhD candidates. A couple of weeks ago, at the end of March her first PhD student defended his thesis successfully. Being a „doctoral mother” she says, is similar to being a regular mum: „You have to invest lots of time, but get back so much.“

But time is crucial for a scientist she admits and experienced this especially when her daughter was newly born. All of a sudden she realized she could not stay in the lab as long as she wanted, and had difficulties to attend conferences abroad. „Being a first-time mother both in science and life brought me to my limits.“ It only worked out, she explains, thanks to the great support of her husband, who also took parental leave, as well as both her mother and mother-in-law came over from China for several months to support her. 

Female networking

Shi´s advice for young women in science: „Communicate more with your loved ones and colleagues.“ She emphasizes that she faced doubts during her PhD and at one point seriously considered leaving academia. Encouragement from her husband and colleagues—especially slightly more senior female scientists who had gone through similar experiences—helped her. “Seeing that others had faced similar challenges and overcome them gave me confidence,” she says. Looking back, she is most grateful to have persevered and succeeded.

Another important pillar in Shi´s career is her passion. Even after many years with nanoporous metals, Shi remains full of admiration. Although only visible with high-resolution microscopes, she enjoys the beautiful nanoarchitecture of her metallic sponges: „They are delicate, yet incredibly strong and multifunctional.“ As with her materials, Shi herself exemplifies the balance of responsibility and adaptability in both her career and family life.