About

Shengfeng Cheng is an Associate Professor in the Department of Physics at Virginia Tech and serves as the Director of The Center for Soft Matter and Biological Physics. His research focuses on theoretical condensed matter physics, with a particular emphasis on soft matter and biological physics. He is based at 115 Robeson Hall, Blacksburg, VA, and can be contacted via email at chengsf@vt.edu or by phone at (540) 231-5767. His academic background includes a Ph.D. from Johns Hopkins University. His work involves exploring the properties and behaviors of complex physical systems, contributing to the understanding of soft matter and biological physics phenomena.

Research topics

• Materials science
• Optoelectronics
• Physics
• Nanotechnology
• Composite material
• Optics
• Chemical physics
• Computational chemistry
• Chemistry
• Biophysics

Selected publications

• Analytical Interaction Potentials for Disks in Two Dimensions

  AIP Publishing · 2026-03-17

  otherOpen access

  Compact analytical forms are derived for the interactions involving thin disks in two dimensions using an integration approach. These include interactions between a disk and a material point, between two disks, and between a disk and a wall. Each object is treated as a continuous medium of materials points interacting by the Lennard-Jones 12-6 potential. By integrating this potential in a pairwise manner, expressions for the potentials and resultant forces between extended objects are obtained. All the results are validated with numerical integrations. The analytical potentials are implemented in LAMMPS and used to simulate two-dimensional suspension of disks with an explicit solvent modeled as a Lennard-Jones liquid. In monodisperse disk suspensions, a disorder-to-order transition of disk packing is observed as the area fraction of disks is increased or as the solvent evaporates. In bidisperse disk suspensions being rapidly dried, stratification is found with the smaller disks enriched at the evaporation front. Such "small-on-top" stratification echoes the similar phenomenon occurring in three-dimensional polydisperse colloidal suspensions that undergo fast drying. These potentials can be applied to a wide range of two-dimensional systems involving disk-like objects.

  PublisherDOI

• Analytical interaction potentials for disks in two dimensions

  The Journal of Chemical Physics · 2026-03-17

  articleSenior author

  Compact analytical forms are derived for the interactions involving thin disks in two dimensions using an integration approach. These include interactions between a disk and a material point, between two disks, and between a disk and a wall. Each object is treated as a continuous medium of materials points interacting by the Lennard-Jones 12-6 potential. By integrating this potential in a pairwise manner, expressions for the potentials and resultant forces between extended objects are obtained. All the results are validated with numerical integrations. The analytical potentials are implemented in LAMMPS and used to simulate two-dimensional suspension of disks with an explicit solvent modeled as a Lennard-Jones liquid. In monodisperse disk suspensions, a disorder-to-order transition of disk packing is observed as the area fraction of disks is increased or as the solvent evaporates. In bidisperse disk suspensions being rapidly dried, stratification is found with the smaller disks enriched at the evaporation front. Such "small-on-top" stratification echoes the similar phenomenon occurring in three-dimensional polydisperse colloidal suspensions that undergo fast drying. These potentials can be applied to a wide range of two-dimensional systems involving disk-like objects.

  PublisherDOI

• Supplemental Material

  AIP Publishing · 2026-03-17

  articleOpen accessSenior author

  Detailed derivations of the analytical forms of the integrated potentials involving disks in two dimensions; Numerical verification of the analytical results on the integrated potentials of disks; Details on the implementation of the analytical potentials of disks in LAMMPS as a user package (DISK); Visualization of a two-dimensional Lennard-Jones liquid film simulated with the user package DISK; Comparison of Langevin and DPD thermostats for simulating drying of disk suspensions in two dimensions; Results on bidisperse disk suspensions dried at an even slower rate.

  PublisherDOI

• Supplemental Material

  AIP Publishing · 2026-03-17

  articleOpen accessSenior author

  Detailed derivations of the analytical forms of the integrated potentials involving disks in two dimensions; Numerical verification of the analytical results on the integrated potentials of disks; Details on the implementation of the analytical potentials of disks in LAMMPS as a user package (DISK); Visualization of a two-dimensional Lennard-Jones liquid film simulated with the user package DISK; Comparison of Langevin and DPD thermostats for simulating drying of disk suspensions in two dimensions; Results on bidisperse disk suspensions dried at an even slower rate.

  PublisherDOI

• Analytical Interaction Potentials for Disks in Two Dimensions

  AIP Publishing · 2026-03-17

  otherOpen access

  Compact analytical forms are derived for the interactions involving thin disks in two dimensions using an integration approach. These include interactions between a disk and a material point, between two disks, and between a disk and a wall. Each object is treated as a continuous medium of materials points interacting by the Lennard-Jones 12-6 potential. By integrating this potential in a pairwise manner, expressions for the potentials and resultant forces between extended objects are obtained. All the results are validated with numerical integrations. The analytical potentials are implemented in LAMMPS and used to simulate two-dimensional suspension of disks with an explicit solvent modeled as a Lennard-Jones liquid. In monodisperse disk suspensions, a disorder-to-order transition of disk packing is observed as the area fraction of disks is increased or as the solvent evaporates. In bidisperse disk suspensions being rapidly dried, stratification is found with the smaller disks enriched at the evaporation front. Such "small-on-top" stratification echoes the similar phenomenon occurring in three-dimensional polydisperse colloidal suspensions that undergo fast drying. These potentials can be applied to a wide range of two-dimensional systems involving disk-like objects.

  PublisherDOI

• Effect of particle shape on stratification in drying films of binary colloidal mixtures

  The Journal of Chemical Physics · 2025-07-17 · 3 citations

  articleSenior author

  The role of particle shape in evaporation-induced auto-stratification in polydisperse colloidal suspensions is explored with molecular dynamics simulations of mixtures of spheres and aspherical particles. A unified framework based on the competition between diffusion and diffusiophoresis is proposed to understand the effects of shape and size dispersity. In general, particles diffusing more slowly (e.g., larger particles) tend to accumulate more strongly at the evaporation front. However, larger particles have larger surface areas and therefore greater diffusiophoretic mobility. Hence, they are more likely to be driven away from the evaporation front via diffusiophoresis. For a rapidly dried bidisperse suspension containing small and large spheres, the competition leads to "small-on-top" stratification. Here, we employ a computational model in which the diffusion coefficient is inversely proportional to particle mass. For a mixture of spheres and aspherical particles with similar mass, the diffusion contrast is reduced, and the spheres are always enriched at the evaporation front as they have the smallest surface area for a given mass and, therefore, the lowest diffusiophoretic mobility. For a mixture of solid and hollow spheres that have the same outer radius and thus the same surface area, the diffusiophoretic contrast is suppressed, and the system is dominated by diffusion. Consequently, the solid spheres, which have a larger mass and diffuse more slowly, accumulate on top of the hollow spheres. Finally, for a mixture of thin disks and long rods that differ significantly in shape but have similar mass and surface area, both diffusion and diffusiophoresis contrasts are suppressed, and the mixture does not stratify.

  PublisherDOI

• Analytical interaction potential for Lennard-Jones rods

  Physical review. E · 2025-01-03 · 3 citations

  articleSenior author

  An analytical form has been derived using Ostrogradsky's integration method for the interaction between two thin rods of finite lengths in arbitrary relative configurations in a three-dimensional space, each treated as a line of point particles interacting through the Lennard-Jones 12-6 potential. Simplified analytical forms for coplanar, parallel, and collinear rods are also derived. Exact expressions for the force and torque between the rods are obtained. Similar results for a point particle interacting with a thin rod are provided. These interaction potentials can be widely used for analytical descriptions and computational modeling of systems involving rodlike objects such as liquid crystals, colloids, polymers, elongated viruses and bacteria, and filamentous materials including carbon nanotubes, nanowires, biological filaments, and their bundles.

  PublisherDOI

• Effect of Particle Shape on Stratification in Drying Films of Binary Colloidal Mixtures

  ArXiv.org · 2025-02-22

  preprintOpen accessSenior author

  The role of particle shape in evaporation-induced auto-stratification in dispersed colloidal suspensions is explored with molecular dynamics simulations of mixtures of solid spheres, aspherical particles, and hollow spheres. A unified framework is proposed for the stratification phenomena in systems that feature size or shape dispersity on the basis of two processes: diffusion and diffusiophoresis. In general, diffusion favors the accumulation of particles that diffuse more slowly at the evaporation front. However, particles with larger surface areas have larger diffusiophoretic mobilities and are more likely to be driven away from the evaporation front by the concentration gradients of other particles with smaller surface areas. In the case of a bidisperse colloidal suspension containing small and large solid spheres studied in most of the work reported in the literature, the competition between the two leads to the so-called "small-on-top" stratification when the suspension is rapidly dried, as diffusiophoresis dominates near the interface. Here we employ a computational model of composite particles that mimics the Rouse model of polymers, where the diffusion coefficient of a particle is inversely proportional to its mass. For a mixture of solid spheres and aspherical particles or hollow spheres with similar masses, the diffusion contrast is reduced and the solid spheres are always enriched at the evaporation front, as they have the smallest surface area for a given mass and therefore the lowest diffusiophoretic mobility. The unified framework is further corroborated with a case study of a mixture of solid and hollow spheres having the same outer radius and thus the same surface area. In this case, the diffusiophoretic contrast is suppressed and the solid spheres, which have a larger mass and thus a smaller diffusion coefficient, are found to accumulate at the evaporation front.

  PublisherOA PDFDOI

• Analytical sphere–thin rod interaction potential

  The European Physical Journal E · 2025-04-07 · 1 citations

  articleOpen accessSenior author

  Abstract A compact analytical form is derived through an integration approach for the interaction between a sphere and a thin rod of finite and infinite lengths, with each object treated as a continuous medium of material points interacting by the Lennard-Jones 12-6 potential and the total interaction potential as a summation of the pairwise potential between material points on the two objects. Expressions for the resultant force and torque are obtained. Various asymptotic limits of the analytical sphere–rod potential are discussed. The integrated potential is applied to investigate the adhesion between a sphere and a thin rod. When the rod is sufficiently long and the sphere sufficiently large, the equilibrium separation between the two (defined as the distance from the center of the sphere to the axis of the rod) is found to be well approximated as $$a+0.787\sigma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>a</mml:mi> <mml:mo>+</mml:mo> <mml:mn>0.787</mml:mn> <mml:mi>σ</mml:mi> </mml:mrow> </mml:math> , where a is the radius of the sphere and $$\sigma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>σ</mml:mi> </mml:math> is the unit of length of the Lennard–Jones potential. Furthermore, the adhesion between the two is found to scale with $$\sqrt{a}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>a</mml:mi> </mml:msqrt> </mml:math> . Graphic abstract)

  PublisherOA PDFDOI

• Analytical Interaction Potentials for Disks in Two Dimensions

  VTechWorks (Virginia Tech) · 2025-11-25

  preprintOpen accessSenior author

  Compact analytical forms are derived for the interactions involving thin disks in two dimensions using an integration approach. These include interactions between a disk and a material point, between two disks, and between a disk and a wall. Each object is treated as a continuous medium of materials points interacting by the Lennard-Jones 12-6 potential. By integrating this potential in a pairwise manner, expressions for the potentials and resultant forces between extended objects are obtained. All the results are validated with numerical integrations. The analytical potentials are implemented in LAMMPS and used to simulate two-dimensional suspension of disks with an explicit solvent modeled as a Lennard-Jones liquid. In monodisperse disk suspensions, a disorder-to-order transition of disk packing is observed as the area fraction of disks is increased or as the solvent evaporates. In bidisperse disk suspensions being rapidly dried, stratification is found with the smaller disks enriched at the evaporation front. Such "small-on-top" stratification echoes the similar phenomenon occurring in three-dimensional polydisperse colloidal suspensions that undergo fast drying. These potentials can be applied to a wide range of two-dimensional systems involving disk-like objects.

  PublisherOA PDFDOI

Recent grants

• CAREER: Nonequilibrium Physics in Drying Soft Matter Solutions

  NSF · $515k · 2020–2026

Frequent coauthors

• Mark J. Stevens

  Sandia National Laboratories

  27 shared

• Gary S. Grest

  Sandia National Laboratories

  27 shared

• Chengyuan Wen

  Zhejiang Ocean University

  21 shared

• Mark O. Robbins

  16 shared

• Michael Chandross

  15 shared

• Yanfei Tang

  Virginia Tech

  14 shared

• George D. Bachand

  Sandia National Laboratories

  10 shared

• Nathan F. Bouxsein

  University of California, Santa Barbara

  10 shared

Labs

• Shengfeng Cheng LaboratoryPI

Education

• Ph.D., Physics and Astronomy

  Johns Hopkins University

  2010

• M.S., Physics

  Nanjing University

  2003

• B.S., Physics

  Nanjing University

  2000