Title：Separationby Porous Membranes and Stability of Patterned Block Copolymer Thin Films

Speaker：Dr. Le Qiao(University Mainz, Germany)

Time：November12th, 2024, 10:00am

Location: C3-c204, Guangzhou International Campus,SCUT

Abstract:

In this talk, I will present our work on applyingparticle-based simulations and self-consistent field theory (SCFT) toinvestigate dynamic and equilibrium properties of polymers in solvent and melt,with a focus on two specific applications:  DNA separation via nanopore electrophoresisand  stability and elasticity ofsphere-patterned block copolymer (BCP) thin films.

The size-and topology-based separation of DNA molecules is essential in molecularanalysis, including genome sequencing, and has broad biochemical and medicalapplications. Standard gel electrophoresis, however, faces limitations such aslow separation efficiency and challenging sample recovery. In the first part ofthis talk, I will discuss our proof-of-concept design for a nanofluidic devicethat leverages nanopores and alternating current fields to achieve size- andtopology-based separation of DNA. Using Langevin dynamics simulations with acoarse-grained bead-spring model, we demonstrate how pulsed field sequencesenable ratcheting of semiflexible DNA chains, allowing only desired chains totranslocate and effectively transforming the nanopore into a low-pass molecularfilter.

The secondpart of the talk will focus on the stability and elasticity of sphere-patternedBCP thin films, structures with diverse technological applications.Experimental results indicate that ultra-thin films with sphere patterns areless stable than other morphologies. To probe this behavior, we used SCFT toexamine the films’ elastic response under deformations such as shear,extension, compression, and bending. Additionally, we developed a simplethree-dimensional SCF algorithm employing real-space methods and non-uniformdiscretization, enhancing simulation accuracy and efficiency for polymericsystems near interfaces.