@article{li_kuang_fuss_zauscher_kokkoli_yingling_2017, title={Salt Responsive Morphologies of ssDNA-Based Triblock Polyelectrolytes in Semi-Dilute Regime: Effect of Volume Fractions and Polyelectrolyte Length}, volume={38}, ISSN={1022-1336}, url={http://dx.doi.org/10.1002/marc.201700422}, DOI={10.1002/marc.201700422}, abstractNote={A comprehensive study is reported on the effect of salt concentration, polyelectrolyte block length, and polymer concentration on the morphology and structural properties of nanoaggregates self-assembled from BAB single-strand DNA (ssDNA) triblock polynucleotides in which A represents polyelectrolyte blocks and B represents hydrophobic neutral blocks. A morphological phase diagram above the gelation point is developed as a function of solvent ionic strength and polyelectrolyte block length utilizing an implicit solvent ionic strength method for dissipative particle dynamics simulations. As the solvent ionic strength increases, the self-assembled DNA network structures shrinks considerably, leading to a morphological transition from a micellar network to worm-like or hamburger-shape aggregates. This study provides insight into the network morphology and its changes by calculating the aggregation number, number of hydrophobic cores, and percentage of bridge chains in the network. The simulation results are corroborated through cryogenic transmission electron microscopy on the example of the self-assembly of ssDNA triblocks.}, number={20}, journal={Macromolecular Rapid Communications}, publisher={Wiley}, author={Li, Nan K. and Kuang, Huihui and Fuss, William H. and Zauscher, Stefan and Kokkoli, Efrosini and Yingling, Yaroslava G.}, year={2017}, month={Sep}, pages={1700422} }
 @article{li_fuss_yingling_2015, title={An Implicit Solvent Ionic Strength (ISIS) Method to Model Polyelectrolyte Systems with Dissipative Particle Dynamics}, volume={24}, ISSN={["1521-3919"]}, url={https://publons.com/publon/9429670/}, DOI={10.1002/mats.201400043}, abstractNote={Herein, a new coarse‐grained methodology for modeling and simulations of polyelectrolyte systems using implicit solvent ionic strength (ISIS) with dissipative particle dynamics (DPD) is presented. This ISIS model is based on mean‐field theory approximation and the soft repulsive potential is used to reproduce the effect of solvent ionic strength. The capability of the ISIS model is assessed via two test cases: dynamics of a single long polyelectrolyte chain and the self‐assembly of polyelectrolyte diblock copolymers in aqueous solutions with variable ionic strength. The results are in good agreement with previous experimental observations and theoretical predictions, which indicates that our polyelectrolyte model can be used to effectively and efficiently capture salt‐dependent conformational features of large‐scale polyelectrolyte systems in aqueous solutions, especially at the salt‐dominated regime.}, number={1}, journal={MACROMOLECULAR THEORY AND SIMULATIONS}, publisher={Wiley-Blackwell}, author={Li, Nan K. and Fuss, William H. and Yingling, Yaroslava G.}, year={2015}, month={Jan}, pages={7–12} }
 @article{li_fuss_tang_gu_chilkoti_zauscher_yingling_2015, title={Prediction of solvent-induced morphological changes of polyelectrolyte diblock copolymer micelles}, volume={11}, ISSN={["1744-6848"]}, url={https://publons.com/wos-op/publon/7980728/}, DOI={10.1039/c5sm01742d}, abstractNote={Self-assembly processes of polyelectrolyte block copolymers are ubiquitous in industrial and biological processes; understanding their physical properties can also provide insights into the design of polyelectrolyte materials with novel and tailored properties. Here, we report systematic analysis on how the ionic strength of the solvent and the length of the polyelectrolyte block affect the self-assembly and morphology of the polyelectrolyte block copolymer materials by constructing a salt-dependent morphological phase diagram using an implicit solvent ionic strength (ISIS) method for dissipative particle dynamics (DPD) simulations. This diagram permits the determination of the conditions for the morphological transition into a specific shape, namely vesicles or lamellar aggregates, wormlike/cylindrical micelles, and spherical micelles. The scaling behavior for the size of spherical micelles is predicted, in terms of radius of gyration (R(g,m)) and thickness of corona (Hcorona), as a function of solvent ionic strength (c(s)) and polyelectrolyte length (NA), which are R(g,m) ∼ c(s)(-0.06)N(A)(0.54) and Hcorona ∼ c(s)(-0.11)N(A)(0.75). The simulation results were corroborated through AFM and static light scattering measurements on the example of the self-assembly of monodisperse, single-stranded DNA block-copolynucleotides (polyT50-b-F-dUTP). Overall, we were able to predict the salt-responsive morphology of polyelectrolyte materials in aqueous solution and show that a spherical-cylindrical-lamellar change in morphology can be obtained through an increase in solvent ionic strength or a decrease of polyelectrolyte length.}, number={42}, journal={SOFT MATTER}, publisher={Royal Society of Chemistry (RSC)}, author={Li, Nan K. and Fuss, William H. and Tang, Lei and Gu, Renpeng and Chilkoti, Ashutosh and Zauscher, Stefan and Yingling, Yaroslava G.}, year={2015}, pages={8236–8245} }