1
|
Wang F, Liu W, Lu R, Huang JH, Zuo B, Wang X. Entropy-Enhanced Mechanochemical Activation for Thermal Degrafting of Surface-Tethered Dry Polystyrene Brushes. ACS Macro Lett 2022; 11:1041-1048. [PMID: 35920565 DOI: 10.1021/acsmacrolett.2c00263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dry polymer brushes have attracted great attention because of their potential utility in regulating interface properties. However, it is still unknown whether dry polymer brushes will exhibit degrafting behavior as a result of thermal annealing. Herein, a study of the conformational entropy effect on thermal degrafting of dry polystyrene (PS) brushes is presented. For PS brushes with an initial grafting density (σpini) of 0.61 nm-2, degrafting behavior was observed at 393 K, and the equilibrium σp was approximately 0.14 nm-2 at 413 K. However, for brushes with σpini ≤ 0.14 nm-2, thermal degrafting was not observed even if the temperature was increased to 453 K. Furthermore, we found that the degrafting rate was faster for PS brushes with higher σpini and higher molecular weights when σpini > 0.14 nm-2. Our findings confirmed that degrafting is a mechanochemical activation process driven by tension imposed on bonds that anchor the chains to the surface, and the process is amplified by conformational entropy.
Collapse
Affiliation(s)
- Fengliang Wang
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Wenqing Liu
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Rongxing Lu
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Jian-Hua Huang
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Biao Zuo
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Xinping Wang
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| |
Collapse
|
2
|
Aktas Eken G, Ober CK. Strong Polyelectrolyte Brushes via Alternating Copolymers of Styrene and Maleimides: Synthesis, Properties, and Stability. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00647] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Gozde Aktas Eken
- Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Christopher K. Ober
- Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| |
Collapse
|
3
|
Ding Z, Chen C, Yu Y, de Beer S. Synthetic strategies to enhance the long-term stability of polymer brush coatings. J Mater Chem B 2022; 10:2430-2443. [DOI: 10.1039/d1tb02605d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High-density, end-anchored macromolecules that form so-called polymer brushes are popular components of bio-inspired surface coatings. In a bio-memetic approach, they have been utilized to reduce friction, repel contamination and control...
Collapse
|
4
|
Hassanpour F, Jalili K, Behboodpour L, Afkhami A. Microstructural Capture of Living Ultrathin Polymer Brush Evolution via Kinetic Simulation Studies. J Phys Chem B 2020; 124:9438-9455. [PMID: 32935990 DOI: 10.1021/acs.jpcb.0c04890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Performing dynamic off-lattice multicanonical Monte Carlo simulations, we study the statics, dynamics, and scission-recombination kinetics of a self-assembled in situ-polymerized polydisperse living polymer brush (LPB), designed by surface-initiated living polymerization. The living brush is initially grown from a two-dimensional substrate by end-monomer polymerization-depolymerization reactions through seeding of initiator arrays on the grafting plane which come in contact with a solution of nonbonded monomers under good solvent conditions. The polydispersity is shown to significantly deviate from the Flory-Schulz type for low temperatures because of pronounced diffusion limitation effects on the rate of the equilibration reaction. The self-avoiding chains take up fairly compact structures of typical size Rg(N) ∼ Nν in rigorously two-dimensional (d = 2) melt, with ν being the inverse fractal dimension (ν = 1/d). The Kratky description of the intramolecular structure factor F(q), in keeping with the concept of generalized Porod scattering from compact particles with fractal contour, discloses a robust nonmonotonic fashion with qdF(q) ∼ (qRg)-3/4 in the intermediate-q regime. It is found that the kinetics of LPB growth, given by the variation of the mean chain length, follows a power law ⟨N(t)⟩ ∝ t1/3 with elapsed time after the onset of polymerization, whereby the instantaneous molecular weight distribution (MWD) of the chains c(N) retains its functional form. The variation of ⟨N(t)⟩ during quenches of the LPB to different temperatures T can be described by a single master curve in units of dimensionless time t/τ∞, where τ∞ is the typical (final temperature T∞-dependent) relaxation time which is found to scale as τ∞ ∝ ⟨N(t = ∞)⟩5 with the ultimate average length of the chains. The equilibrium monomer density profile ϕ(z) of the LPB varies as ϕ(z) ∝ ϕ-α with the concentration of segments ϕ in the system and the probability distribution c(N) of chain lengths N in the brush layer scales as c(N) ∝ N-τ. The computed exponents α ≈ 0.64 and τ ≈ 1.70 are in good agreement with those predicted within the context of the Diffusion-Limited Aggregation theory, α = 2/3 and τ = 7/4.
Collapse
Affiliation(s)
- Fatemeh Hassanpour
- Department of Polymer Engineering, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran.,Institute of Polymeric Materials, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran
| | - Kiyumars Jalili
- Department of Polymer Engineering, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran.,Institute of Polymeric Materials, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran
| | - Leila Behboodpour
- Department of Polymer Engineering, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran.,Institute of Polymeric Materials, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran
| | - Ali Afkhami
- Department of Polymer Engineering, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran.,Institute of Polymeric Materials, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran
| |
Collapse
|
5
|
Brió
Pérez M, Cirelli M, de Beer S. Degrafting of Polymer Brushes by Exposure to Humid Air. ACS APPLIED POLYMER MATERIALS 2020; 2:3039-3043. [PMID: 34124685 PMCID: PMC8192051 DOI: 10.1021/acsapm.0c00474] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/08/2020] [Indexed: 05/22/2023]
Abstract
It is well-known that polymer brushes can degraft in aqueous liquids. Here we show that brushes can deteriorate in humid air too. We observe that the detachment rate of the brushes increases with increasing relative humidity and hydrophilicity of the brushes. We relate this to the increase in water absorption as these parameters are increased. Our results imply that protective measures that are at present being developed for applications of brushes in liquids will also be key in enabling the long-term storage and utilization of hydrophilic brushes in air.
Collapse
Affiliation(s)
- Maria Brió
Pérez
- Materials Science and Technology of
Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Marco Cirelli
- Materials Science and Technology of
Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Sissi de Beer
- Materials Science and Technology of
Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| |
Collapse
|
6
|
Ko Y, Christau S, von Klitzing R, Genzer J. Charge Density Gradients of Polymer Thin Film by Gaseous Phase Quaternization. ACS Macro Lett 2020; 9:158-162. [PMID: 35638676 DOI: 10.1021/acsmacrolett.9b00930] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report on the rapid formation of charge density gradients in polymer films by exposing poly([2-dimethylaminoethyl] methacrylate) (PDMAEMA) films resting on flat silica substrates to methyl iodide (i.e., MI, also known as iodomethane) vapors. We adjust the charge gradient by varying the MI concentration in solution and the process time. The thickness of the parent PDMAEMA film does not affect the diffusion of MI through and the reaction kinetics in the films. Instead, the diffusion of MI through the gaseous phase constitutes the limiting step in the overall process.
Collapse
Affiliation(s)
- Yeongun Ko
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Stephanie Christau
- Department of Chemical Engineering, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Regine von Klitzing
- Department of Physics, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - Jan Genzer
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States.,Global Station for Soft Matter, Global Institution for Collaborative Research and Education Hokkaido University, Sapporo, 060-0808, Japan
| |
Collapse
|
7
|
Agergaard AH, Pedersen SU, Birkedal H, Daasbjerg K. Stimuli-responsive degrafting of polymer brushes via addressable catecholato-metal attachments. Polym Chem 2020. [DOI: 10.1039/d0py00916d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Surface attached catecholato-metal complexes serve as polymer brush initiators with well-defined densities and enable stimuli-responsive degrafting of polymer brushes.
Collapse
Affiliation(s)
- Asger Holm Agergaard
- Interdisciplinary Nanoscience Center (iNANO) Aarhus University
- Aarhus C DK-8000
- Denmark
- Department of Chemistry
- Aarhus University
| | - Steen Uttrup Pedersen
- Interdisciplinary Nanoscience Center (iNANO) Aarhus University
- Aarhus C DK-8000
- Denmark
- Department of Chemistry
- Aarhus University
| | - Henrik Birkedal
- Interdisciplinary Nanoscience Center (iNANO) Aarhus University
- Aarhus C DK-8000
- Denmark
- Department of Chemistry
- Aarhus University
| | - Kim Daasbjerg
- Interdisciplinary Nanoscience Center (iNANO) Aarhus University
- Aarhus C DK-8000
- Denmark
- Department of Chemistry
- Aarhus University
| |
Collapse
|
8
|
Li Y, Lin Y, Dai Y, Ko Y, Genzer J. Mechanochemical Degrafting of a Surface-Tethered Poly(acrylic acid) Brush Promoted Etching of Its Underlying Silicon Substrate. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:13693-13699. [PMID: 31565947 DOI: 10.1021/acs.langmuir.9b02610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The stability of surface-tethered polyelectrolyte brushes has been investigated during the past few years. We have previously reported on the degrafting of poly(acrylic acid) (PAA) polymer brushes from flat silicon substrates. Here, we present a detailed study on the effects of NaCl concentration and the grafting density and molecular weight on the stability of PAA brushes during incubation in 0.1 M ethanolamine buffer (pH 9.0) solutions. Without NaCl in the buffer solution, the PAA brushes remain intact. Adding NaCl facilitates etching of the substrate due to accelerating dissolution of the top silica layer and promoting degrafting of the PAA chains. The PAA grafting density and molecular weight play an important role in the substrate etching by affecting the penetration barrier and local concentration of the etchants. We also tested the stability of self-assembled monolayers (SAMs) made of hydrophobic alkyltrichlorosilanes anchored on silicon substrates. The results demonstrated that the SAMs were too thin to protect the substrates from etching, in contrast to thick poly(methyl methacrylate) brushes. Our findings suggest that both polymer brushes (especially polyelectrolyte brushes) and SAMs anchored to silicon substrates may undergo erosion/etching on the substrates in basic environments, which compromises their stability and therefore jeopardizes their applications in coating, biosensing, and so forth.
Collapse
Affiliation(s)
- Yuanchao Li
- Key Laboratory of Polymeric Composite & Functional Materials of Ministry of Education, School of Materials Science and Engineering , Sun Yat-Sen University , No. 135 Xingang Xi Road , Guangzhou 510275 , China
| | - Yiliang Lin
- Department of Chemical & Biomolecular Engineering , North Carolina State University , 911 Partners Way , Raleigh , North Carolina 27695-7905 , United States
| | - Yunkai Dai
- Key Laboratory of Polymeric Composite & Functional Materials of Ministry of Education, School of Materials Science and Engineering , Sun Yat-Sen University , No. 135 Xingang Xi Road , Guangzhou 510275 , China
| | - Yeongun Ko
- Department of Chemical & Biomolecular Engineering , North Carolina State University , 911 Partners Way , Raleigh , North Carolina 27695-7905 , United States
| | - Jan Genzer
- Department of Chemical & Biomolecular Engineering , North Carolina State University , 911 Partners Way , Raleigh , North Carolina 27695-7905 , United States
| |
Collapse
|