1
|
Moncure P, Millstone JE, Laaser JE. Role of Ligand Shell Density in the Diffusive Behavior of Nanoparticles in Hydrogels. J Phys Chem B 2023; 127:9366-9377. [PMID: 37857360 PMCID: PMC10626584 DOI: 10.1021/acs.jpcb.3c03249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 09/01/2023] [Indexed: 10/21/2023]
Abstract
The diffusion coefficients of poly(ethylene glycol) methyl ether thiol (PEGSH)-functionalized gold nanoparticles (NPs) with different effective grafting densities were measured in polyacrylamide hydrogels. The NP core size was held constant, and the NPs were functionalized with mixtures of short oligomeric ligands (254 Da PEGSH) and longer (either 1 or 2 kDa PEGSH) ligands. The ratio of short and long ligands was varied such that the grafting density of the high-molecular-weight (MW) ligand ranged from approximately 1 to 100 high-MW ligands/NP. The diffusion coefficients of the NPs were then measured in gels with varying average mesh sizes. The measured diffusion coefficients decreased with higher MW ligand density. Interestingly, the diffusion coefficients for NPs with high effective grafting densities were well-predicted by their hydrodynamic diameters, but the diffusion coefficients for NPs with low effective grafting densities were higher than expected from their hydrodynamic diameters. These results suggest that crowding in the NP ligand shell influences the mechanism of diffusion, with lower grafting densities allowing ligand chain relaxations that facilitate movement through the gel. This work brings new insights into the factors that dictate how NPs move through hydrogels and will inform the development of models for applications such as drug delivery in complex viscoelastic biological materials.
Collapse
Affiliation(s)
- Paige
J. Moncure
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Jill E. Millstone
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Jennifer E. Laaser
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| |
Collapse
|
2
|
Zhang S, Wang J, Ge T. Force-driven active dynamics of thin nanorods in unentangled polymer melts. SOFT MATTER 2022; 18:6582-6591. [PMID: 35968884 DOI: 10.1039/d2sm00731b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Recent advances in the functional material and biomedical applications of nanorods call for a fundamental understanding of the active motion of nanorods in a viscoelastic medium. Molecular dynamics simulations are performed to investigate a model system consisting of force-driven active thin nanorods in a melt of unentangled polymers. The activeness of a thin nanorod arises from a constant external force applied uniformly along the rod. The simulations demonstrate that the active force overcomes the randomness of the diffusive motion and results in a ballistic motion along the direction of the applied force at long timescales. The constant speed of the force-driven ballistic motion is determined by the balance of the active force and the friction from the coupling of the nanorod with the polymer viscosity. The friction coefficient, which is computed as the ratio of the active force and the speed, decreases as the active force increases. The origin of the reduction in the friction coefficient is the high speed that allows the nanorod to renew its local environment faster than the relaxation time of melt chains. A scaling theory is developed to quantify the dependence of the friction coefficient on the strength of the active force. The simulations also demonstrate that the force-driven ballistic motion suppresses the rotational diffusion of the rod and cuts off the de-correlation of the rod axis with time. On the scaling level, the long-time trajectory of a force-driven active nanorod piercing through unentangled polymers may be described as a stretched array of "active blobs", where the short-time random-walk trajectory within an active blob is unperturbed by the active force.
Collapse
Affiliation(s)
- Siteng Zhang
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA.
| | - Jiuling Wang
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA.
| | - Ting Ge
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA.
| |
Collapse
|
3
|
Chen Y, Xu H, Ma Y, Liu J, Zhang L. Diffusion of polymer-grafted nanoparticles with dynamical fluctuations in unentangled polymer melts. Phys Chem Chem Phys 2022; 24:11322-11335. [PMID: 35485911 DOI: 10.1039/d2cp00002d] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The dynamics of polymer-grafted nanoparticles (PGNPs) in melts of unentangled linear chains were investigated by means of coarse-grained molecular dynamics simulations. The results demonstrated that the graft monomers closer to the particle surface relax more slowly than those farther away due to the constraint of the grafted surface and the confinement of the neighboring chains. Such heterogeneous relaxations of the surrounding environment would perturb the particle motion, making them fluctuating around their centers before they can diffuse through the melt. During such intermediate-time stage, the dynamics is subdiffusive while the distribution of particle displacements is Gaussian, which can be described by the popular fractional Brownian motion model. For the long-time Fickian diffusion, we found that the diffusivity D decreases with increasing grafting density Σg, grafted chain length Ng, and matrix chain length Nm. This is due to the fact that the diffusivity is controlled by the viscous drag of an effective core, consisting of the NP and the non-draining layer of graft segments, and that of the free-draining graft layer outside the "core". With increasing Σg, the PGNPs become harder with greater effective size and thinner free draining layer, resulting in a reduction in D. At extremely high Σg, the diffusivity can even be estimated by the diameter-renormalized Stokes-Einstein (SE) relation. With increasing Ng, both the effective core size and the thickness of the free-draining layer increase, leading to a reduction in diffusivity by D ∼ N-γg with 0.5 < γ < 1. Increasing Nm would lead to the enlargement of the effective core size but meanwhile result in the reduction of the free-draining layer thickness due to autophobic dewetting. The counteraction between these two opposite effects leads to only a slight reduction in the diffusivity, significantly different from the typical SE behavior where D ∼ Nm-1. These findings bear significance in unraveling the fundamental physics of the anomalous dynamics of PGNPs in various polymers, including biological and synthetic.
Collapse
Affiliation(s)
- Yulong Chen
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Haohao Xu
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Yangwei Ma
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Jun Liu
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Liqun Zhang
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China.
| |
Collapse
|
4
|
Zhang X, Wei W, Xiong H. Hierarchical Dynamics of Nonsticky Molecular Nanoparticle-Tethered Polymers: End and Topology Effects. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
5
|
Ge T, Cheng S, Tg. Physicochemical properties of respiratory droplets and their role in COVID-19 pandemics: a critical review. BIOMATERIALS TRANSLATIONAL 2021; 2:10-18. [PMID: 35837254 PMCID: PMC9255823 DOI: 10.3877/cma.j.issn.2096-112x.2021.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/24/2020] [Accepted: 12/29/2020] [Indexed: 01/10/2023]
Abstract
The ongoing coronavirus disease 2019 (COVID-19) pandemic is a serious challenge faced by the global community. Physical scientists can help medical workers and biomedical scientists, engineers, and practitioners, who are working on the front line, to slow down and eventually contain the spread of the COVID-19 virus. This review is focused on the physicochemical characteristics, including composition, aerodynamics, and drying behavior of respiratory droplets as a complex and multicomponent soft matter system, which are the main carrier of the virus for interpersonal transmission. The distribution and dynamics of virus particles within a droplet are also discussed. Understanding the characteristics of virus-laden respiratory droplets can lead to better design of personal protective equipment, frequently touched surfaces such as door knobs and touchscreens, and filtering equipment for indoor air circulation. Such an understanding also provides the scientific basis of public policy, including social distancing rules and public hygiene guidelines, implemented by governments around the world.
Collapse
Affiliation(s)
- Ting Ge
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, USA,Corresponding authors: Ting Ge, ; Shengfeng Cheng,
| | - Shengfeng Cheng
- Department of Physics, Department of Mechanical Engineering, Center for Soft Matter and Biological Physics, and Macromolecules Innovation Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA,Corresponding authors: Ting Ge, ; Shengfeng Cheng,
| | | |
Collapse
|
6
|
Wang L, Ma J, Hong W, Zhang H, Lin J. Nanoscale Diffusion of Polymer-Grafted Nanoparticles in Entangled Polymer Melts. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00721] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Liquan Wang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Jun Ma
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Wei Hong
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Haojing Zhang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Jiaping Lin
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| |
Collapse
|
7
|
Gkolfi E, Bačová P, Harmandaris V. Size and Shape Characteristics of Polystyrene and Poly(ethylene oxide) Star Polymer Melts Studied By Atomistic Simulations. MACROMOL THEOR SIMUL 2020. [DOI: 10.1002/mats.202000067] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Eirini Gkolfi
- Department of Mathematics and Applied Mathematics University of Crete Heraklion Crete GR‐71409 Greece
- Institute of Applied and Computational Mathematics (IACM) Foundation for Research and Technology Hellas (FORTH) Heraklion Crete GR‐70013 Greece
| | - Petra Bačová
- Institute of Applied and Computational Mathematics (IACM) Foundation for Research and Technology Hellas (FORTH) Heraklion Crete GR‐70013 Greece
| | - Vagelis Harmandaris
- Department of Mathematics and Applied Mathematics University of Crete Heraklion Crete GR‐71409 Greece
- Institute of Applied and Computational Mathematics (IACM) Foundation for Research and Technology Hellas (FORTH) Heraklion Crete GR‐70013 Greece
- Computation‐Based Science and Technology Research Center The Cyprus Institute 20 Constantinou Kavafi Str. Nicosia 2121 Cyprus
| |
Collapse
|
8
|
Ge T, Rubinstein M, Grest GS. Effects of Tethered Polymers on Dynamics of Nanoparticles in Unentangled Polymer Melts. Macromolecules 2020; 53:6898-6906. [PMID: 34366485 DOI: 10.1021/acs.macromol.9b01921] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Polymer-tethered nanoparticles (NPs) are commonly added to a polymer matrix to improve material properties. Critical to the fabrication and processing of such composites is the mobility of the tethered NPs. Here we study the motion of tethered-NPs in unentangled polymer melts using molecular dynamics simulations, which offer a precise control of the grafted chain length N g and the number z of grafted chains per particle. As N g increases, there is a crossover from particle-dominated to tethered-chain-dominated terminal diffusion of NPs with the same z. The mean squared displacement of loosely tethered NPs in the case of tethered-chain dominated terminal diffusion exhibits two sub-diffusive regimes at intermediate time scales for small z. The first one at shorter time scales arises from the dynamical coupling of the particle and matrix chains, while the one at longer time scales is due to the participation of the particle in the dynamics of the tethered chains. The friction of loosely grafted chains in unentangled melts scales linearly with the total number of monomers in the chains, as the frictions of individual monomers are additive in the absence of hydrodynamic coupling. As more chains are grafted to a particle, hydrodynamic interactions between grafted chains emerge. As a result, there is a non-draining layer of hydrodynamically coupled chain segments surrounding the bare particle. Outside the non-draining layer is a free-draining layer of grafted chain segments with no hydrodynamic coupling. The boundary of the two layers is the stick surface where the shear stress due to the relative melt flow is balanced by the friction between grafted and melt chains in the interpenetration layer. The stick surface is located further away from the bare surface of the particle with higher grafting density.
Collapse
Affiliation(s)
- Ting Ge
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA
| | - Michael Rubinstein
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA.,Departments of Biomedical Engineering, Chemistry, and Physics, Duke University, Durham, North Carolina 27708, USA
| | - Gary S Grest
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| |
Collapse
|
9
|
Chen Y, Ma R, Qian X, Zhang R, Huang X, Xu H, Zhou M, Liu J. Nanoparticle Mobility within Permanently Cross-Linked Polymer Networks. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00334] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Yulong Chen
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Rui Ma
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Xin Qian
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Ruoyu Zhang
- Key Laboratory of Bio-based Polymeric Materials Technology and Application of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Xifu Huang
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China
- Ningbo Detai Chemical Co., Ltd., Ningbo 315204, China
| | - Haohao Xu
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Mi Zhou
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Jun Liu
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
| |
Collapse
|
10
|
Jia XM, Qian HJ, Lu ZY. The interfacial structure and dynamics in a polymer nanocomposite containing small attractive nanoparticles: a full atomistic molecular dynamics simulation study. Phys Chem Chem Phys 2020; 22:11400-11408. [PMID: 32374336 DOI: 10.1039/d0cp00799d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We study the interfacial structure and dynamics of a polymer nanocomposite (PNC) composed of octaaminophenyl polyhedral oligomeric silsesquioxane (OAPS) and poly(2-vinylpyridine) (P2VP) by performing full atomistic molecular dynamics simulations. There are eight aminophenyl groups grafted on the surface of the OAPS particle and the particle has a size comparable to the Kuhn segment of P2VP. These aminophenyl groups can form hydrogen bonds (HBs) with pyridine rings from surrounding P2VP chains. We found that OAPS can form ∼2 HBs on average with surrounding polymer chains. The effect of the HBs is investigated in detail by either switching on or off these HBs in our simulation. By analyzing the interfacial static packing structure and dynamic properties, we demonstrate that the system has an ∼1 nm interface width, similar to the OAPS particle size. We also found that HBs can prevent the further penetration of polymers into the inner zone (grafting layer) of the OAPS, and therefore keep the P2VP chains in the outer layer (>1 nm), remaining bulk-like, which is well consistent with experimental results. In addition, we found that NP diffusion is coupled to the absorbed polymer chains, which also dramatically slows down the diffusion of polymer segments in return. The core-shell model in which the NP and absorbed polymers diffuse as a single object is validated here at the full atomistic level. These results provide atomistic insights into the unique structure and dynamics in the small attractive NP-polymer interfacial region. We hope these results will be helpful for the understanding of peculiar phenomena in attractive polymer nanocomposites containing small NPs.
Collapse
Affiliation(s)
- Xiang-Meng Jia
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun 130021, China.
| | | | | |
Collapse
|