We study experimental soft matter physics, focusing on the mechanics of soft materials and complex fluids. Our primary approach involves precise imaging and mechanical measurements to probe material properties across a wide range of length and time scales. These studies uncover nonlinear phenomena that challenge and expand our current understanding of soft material mechanics. The insights we gain directly inform the design of next-generation smart materials. While grounded in fundamental physics, our research also extends into diverse fields such as materials science, biology, and mechanical engineering.
Our research group (Group X: @softmat_hkust) is located at the scenic HKUST campus on Clear Water Bay (清水灣). We are seeking motivated students and postdocs to join our lab. Please check the opening information for updated hiring information.
Selected Publications
[1] Mechanical non-reciprocity programmed by shear jamming in soft composite solids
Chang Xu#, Shuaihu Wang#, Hong Wang#, Xu Liu, Zemin Liu, Yiqiu Zhao*, Wenqi Hu*, Qin Xu*
Nature Materials, 25, 117-123 (2026) / Published online: Nov. 7, 2025
[2] Elasticity-controlled jamming criticality in soft composite solids
Yiqiu Zhao*, Haitao Hu, Yulu Huang, Hanqing Liu, Caishan Yan, Chang Xu, Rui Zhang, Yifan Wang, and Qin Xu*
Nature Communications, 15, 1691 (2024)
[3] Non-monotonic Rheology and Stress Heterogeneity in Confined Granular Suspensions
Haitao Hu, Yiqiu Zhao, Weiwei Zhao, Ligen Qiao, and Qin Xu*
Journal of Rheology, 68, 949-958 (2024)
[4] Emergence and Growth Dynamics of Wetting-induced Phase Separation on Soft Solids
Wenjie Qian, Weiwei Zhao, Tiezheng Qian, and Qin Xu*
Physical Review Research, 6, 033210 (2024)
[5] The role of crosslinking density in surface stress and surface energy of soft solids
Weiwei Zhao, Jianhui Zhou, Haitao Hu, Chang Xu, and Qin Xu*
Soft Matter, 18, 507 (2022)
[6] Viscoelastic and poroelastic relaxations on soft solid surfaces
Qin Xu*, Lawrence Wilen, Katharine E. Jensen, Robert W. Style, and Eric R. Dufresne*
Physical Review Letters, 125, 238002 (2020)
[7] Direct measurements of surface stress of stretched soft solids
Qin Xu, Katharine E. Jensen, Rostislav Boltyanskiy, Raphael Sarfati, Robert Style, and Eric R. Dufresne*
Nature Communications 8, 555 (2017)
[8] Effect of oxidation on the mechanical properties of liquid gallium and eutectic gallium-indium
Qin Xu, Nikolai Oudalov, Qiti Guo, Heinrich M. Jaeger, and Eric Brown*
Physics of Fluids, 24, 063101 (2012)
[9] Subdiffusion of a Sticky Particle on a Surface
Q. Xu*, L. Feng, R. Sha, N. C. Seeman, and P. M. Chaikin
Physical Review Letters, 106, 228102 (2011)
Complex Fluids and Soft Matter @ HKUST 