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Kong Y, Ma S, Zhou F. Bioinspired Interfacial Friction Control: From Chemistry to Structures to Mechanics. Biomimetics (Basel) 2024; 9:200. [PMID: 38667211 PMCID: PMC11048105 DOI: 10.3390/biomimetics9040200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/22/2024] [Accepted: 03/22/2024] [Indexed: 04/28/2024] Open
Abstract
Organisms in nature have evolved a variety of surfaces with different tribological properties to adapt to the environment. By studying, understanding, and summarizing the friction and lubrication regulation phenomena of typical surfaces in nature, researchers have proposed various biomimetic friction regulation theories and methods to guide the development of new lubrication materials and lubrication systems. The design strategies for biomimetic friction/lubrication materials and systems mainly include the chemistry, surface structure, and mechanics. With the deepening understanding of the mechanism of biomimetic lubrication and the increasing application requirements, the design strategy of multi-strategy coupling has gradually become the center of attention for researchers. This paper focuses on the interfacial chemistry, surface structure, and surface mechanics of a single regulatory strategy and multi-strategy coupling approach. Based on the common biological friction regulation mechanism in nature, this paper reviews the research progress on biomimetic friction/lubrication materials in recent years, discusses and analyzes the single and coupled design strategies as well as their advantages and disadvantages, and describes the design concepts, working mechanisms, application prospects, and current problems of such materials. Finally, the development direction of biomimetic friction lubrication materials is prospected.
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Affiliation(s)
- Yunsong Kong
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China; (Y.K.); (F.Z.)
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuanhong Ma
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China; (Y.K.); (F.Z.)
| | - Feng Zhou
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China; (Y.K.); (F.Z.)
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2
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Polymer brushes for friction control: Contributions of molecular simulations. Biointerphases 2023; 18:010801. [PMID: 36653299 DOI: 10.1116/6.0002310] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
When polymer chains are grafted to solid surfaces at sufficiently high density, they form brushes that can modify the surface properties. In particular, polymer brushes are increasingly being used to reduce friction in water-lubricated systems close to the very low levels found in natural systems, such as synovial joints. New types of polymer brush are continually being developed to improve with lower friction and adhesion, as well as higher load-bearing capacities. To complement experimental studies, molecular simulations are increasingly being used to help to understand how polymer brushes reduce friction. In this paper, we review how molecular simulations of polymer brush friction have progressed from very simple coarse-grained models toward more detailed models that can capture the effects of brush topology and chemistry as well as electrostatic interactions for polyelectrolyte brushes. We pay particular attention to studies that have attempted to match experimental friction data of polymer brush bilayers to results obtained using molecular simulations. We also critically look at the remaining challenges and key limitations to overcome and propose future modifications that could potentially improve agreement with experimental studies, thus enabling molecular simulations to be used predictively to modify the brush structure for optimal friction reduction.
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3
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Bioinspired Bottlebrush Polymers for Aqueous Boundary Lubrication. Polymers (Basel) 2022; 14:polym14132724. [PMID: 35808769 PMCID: PMC9269121 DOI: 10.3390/polym14132724] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 06/30/2022] [Accepted: 07/01/2022] [Indexed: 01/30/2023] Open
Abstract
An extremely efficient lubrication system is achieved in synovial joints by means of bio-lubricants and sophisticated nanostructured surfaces that work together. Molecular bottlebrush structures play crucial roles for this superior tribosystem. For example, lubricin is an important bio-lubricant, and aggrecan associated with hyaluronan is important for the mechanical response of cartilage. Inspired by nature, synthetic bottlebrush polymers have been developed and excellent aqueous boundary lubrication has been achieved. In this review, we summarize recent experimental investigations of the interfacial lubrication properties of surfaces coated with bottlebrush bio-lubricants and bioinspired bottlebrush polymers. We also discuss recent advances in understanding intermolecular synergy in aqueous lubrication including natural and synthetic polymers. Finally, opportunities and challenges in developing efficient aqueous boundary lubrication systems are outlined.
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4
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Phospholipids and Hyaluronan: From Molecular Interactions to Nano- and Macroscale Friction. COLLOIDS AND INTERFACES 2022. [DOI: 10.3390/colloids6030038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Phospholipids and hyaluronan are two key biomolecules that contribute to the excellent lubrication of articular joints. Phospholipids alone and in combination with hyaluronan have also displayed low friction forces on smooth surfaces in micro- and nanosized tribological contacts. In an effort to develop aqueous-based lubrication systems, it is highly relevant to explore if these types of molecules also are able to provide efficient lubrication of macroscopic tribological contacts involving surfaces with roughness larger than the thickness of the lubricating layer. To this end, we investigated the lubrication performance of hyaluronan, the phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and mixtures of these two components using glass surfaces in a mini-traction machine. We compared our data with those obtained using flat silica surfaces in previous atomic force microscopy studies, and we also highlighted insights on hyaluronan–phospholipid interactions gained from recent simulations. Our data demonstrate that hyaluronan alone does not provide any lubricating benefit, but DPPC alone and in mixtures with hyaluronan reduces the friction force by an order of magnitude.
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Moon HH, Choi EJ, Yun SH, Kim YC, Premkumar T, Song C. Aqueous lubrication and wear properties of nonionic bottle-brush polymers. RSC Adv 2022; 12:17740-17746. [PMID: 35765345 PMCID: PMC9199083 DOI: 10.1039/d2ra02711a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/09/2022] [Indexed: 11/21/2022] Open
Abstract
The usage of aqueous lubricants in eco-friendly bio-medical friction systems has attracted significant attention. Several bottle-brush polymers with generally ionic functional groups have been developed based on the structure of biological lubricant lubricin. However, hydrophilic nonionic brush polymers have attracted less attention, especially in terms of wear properties. We developed bottle-brush polymers (BP) using hydrophilic 2-hydroxyethyl methacrylate (HEMA), a highly biocompatible yet nonionic molecule. The lubrication properties of polymer films were analyzed in an aqueous state using a ball-on-disk, which revealed that BPHEMA showed a lower aqueous friction coefficient than linear poly(HEMA), even lower than hyaluronic acid (HA) and polyvinyl alcohol (PVA), which are widely used as lubricating polymers. Significantly, we discovered that the combination of HA, PVA, and BPHEMA is demonstrated to be essential in influencing the surface wear properties; the ratio of 1 : 2 (HA : BPHEMA) had the maximum wear resistance, despite a slight increase in the aqueous friction coefficient.
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Affiliation(s)
- Hwi Hyun Moon
- Department of Chemistry, Sungkyunkwan University Suwon Gyeonggi 16419 Republic of Korea
| | - Eun Jung Choi
- Department of Chemistry, Sungkyunkwan University Suwon Gyeonggi 16419 Republic of Korea
| | - Sang Ho Yun
- Department of Chemistry, Sungkyunkwan University Suwon Gyeonggi 16419 Republic of Korea
| | - Youn Chul Kim
- Department of Chemical Engineering, Sungkyunkwan University Suwon Gyeonggi 16419 Republic of Korea
| | - Thathan Premkumar
- Department of Chemistry, Sungkyunkwan University Suwon Gyeonggi 16419 Republic of Korea .,The University College, Sungkyunkwan University Suwon Gyeonggi 16419 Republic of Korea
| | - Changsik Song
- Department of Chemistry, Sungkyunkwan University Suwon Gyeonggi 16419 Republic of Korea
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6
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Feng S, Liu Y, Li J, Wen S. Superlubricity Achieved with Zwitterionic Brushes in Diverse Conditions Induced by Shear Actions. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00430] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Shaofei Feng
- State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
| | - Yuhong Liu
- State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
| | - Jinjin Li
- State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
| | - Shizhu Wen
- State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
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7
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Lin W, Klein J. Recent Progress in Cartilage Lubrication. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2005513. [PMID: 33759245 DOI: 10.1002/adma.202005513] [Citation(s) in RCA: 136] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 11/23/2020] [Indexed: 05/18/2023]
Abstract
Healthy articular cartilage, covering the ends of bones in major joints such as hips and knees, presents the most efficiently-lubricated surface known in nature, with friction coefficients as low as 0.001 up to physiologically high pressures. Such low friction is indeed essential for its well-being. It minimizes wear-and-tear and hence the cartilage degradation associated with osteoarthritis, the most common joint disease, and, by reducing shear stress on the mechanotransductive, cartilage-embedded chondrocytes (the only cell type in the cartilage), it regulates their function to maintain homeostasis. Understanding the origins of such low friction of the articular cartilage, therefore, is of major importance in order to alleviate disease symptoms, and slow or even reverse its breakdown. This progress report considers the relation between frictional behavior and the cellular mechanical environment in the cartilage, then reviews the mechanism of lubrication in the joints, in particular focusing on boundary lubrication. Following recent advances based on hydration lubrication, a proposed synergy between different molecular components of the synovial joints, acting together in enabling the low friction, has been proposed. Additionally, recent development of natural and bio-inspired lubricants is reviewed.
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Affiliation(s)
- Weifeng Lin
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Jacob Klein
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 76100, Israel
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Rahimi M, Charmi G, Matyjaszewski K, Banquy X, Pietrasik J. Recent developments in natural and synthetic polymeric drug delivery systems used for the treatment of osteoarthritis. Acta Biomater 2021; 123:31-50. [PMID: 33444800 DOI: 10.1016/j.actbio.2021.01.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 12/15/2020] [Accepted: 01/05/2021] [Indexed: 12/11/2022]
Abstract
Osteoarthritis (OA), is a common musculoskeletal disorder that will progressively increase in older populations and is expected to be the most dominant cause of disability in the world population by 2030. The progression of OA is controlled by a multi-factorial pathway that has not been completely elucidated and understood yet. However, over the years, research efforts have provided a significant understanding of some of the processes contributing to the progression of OA. Both cartilage and bone degradation processes induce articular cells to produce inflammatory mediators that produce proinflammatory cytokines that block the synthesis of collagen type II and aggrecan, the major components of cartilage. Systemic administration and intraarticular injection of anti-inflammatory agents are the first-line treatments of OA. However, small anti-inflammatory molecules are rapidly cleared from the joint cavity which limits their therapeutic efficacy. To palliate this strong technological drawback, different types of polymeric materials such as microparticles, nanoparticles, and hydrogels, have been examined as drug carriers for the delivery of therapeutic agents to articular joints. The main purpose of this review is to provide a summary of recent developments in natural and synthetic polymeric drug delivery systems for the delivery of anti-inflammatory agents to arthritic joints. Furthermore, this review provides an overview of the design rules that have been proposed so far for the development of drug carriers used in OA therapy. Overall it is difficult to state clearly which polymeric platform is the most efficient one because many advantages and disadvantages could be pointed to both natural and synthetic formulations. That requires further research in the near future.
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10
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A single-component, cross-linked, and surface-grafted polyelectrolyte film fabricated by the layer-by-layer assembly method. POLYMER 2020. [DOI: 10.1016/j.polymer.2020.122524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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12
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Sun Z, Bonassar LJ, Putnam D. Influence of Block Length on Articular Cartilage Lubrication with a Diblock Bottle-Brush Copolymer. ACS APPLIED MATERIALS & INTERFACES 2020; 12:330-337. [PMID: 31855406 DOI: 10.1021/acsami.9b18933] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report how the tribological properties of a class of diblock copolymers with architecture and function inspired by the lubricating glycoprotein lubricin correlate to chemical composition. This class of diblock copolymers, consisting of a cationic cartilage-binding block and a brush-lubricating block, demonstrates that boundary lubrication of articular cartilage more strongly depends on the cartilage-binding block than the lubrication block. Specifically, the cartilage-binding functional groups (tertiary or quaternary amines) and cartilage-binding block length significantly influence the degree of lubrication under boundary mode experimental conditions. An optimal number (∼24 in this case) of cartilage-binding groups led to the lowest coefficient of friction, and an increase or decrease in the number of cations in the binding block led to partial (>24, and between 12 and 24) or complete (=12) loss of lubricating ability. The length of the lubricating block (DP = 200 or 400) chosen in this study had no effect on the degree of lubrication. These results are put into context in terms of binding affinity to the cartilage and the spatial packing density of the polymer on the cartilage surface and can serve as a useful guide for future designs of synthetic lubricants that rival the efficacy of natural lubricants.
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Affiliation(s)
- Zhexun Sun
- Meinig School of Biomedical Engineering , Cornell University , Ithaca , New York 14850 , United States
| | - Lawrence J Bonassar
- Meinig School of Biomedical Engineering , Cornell University , Ithaca , New York 14850 , United States
- Sibley School of Mechanical and Aerospace Engineering , Cornell University , Ithaca , New York 14850 , United States
| | - David Putnam
- Meinig School of Biomedical Engineering , Cornell University , Ithaca , New York 14850 , United States
- Smith School of Chemical and Biomolecular Engineering , Cornell University , Ithaca , New York 14850 , United States
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13
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Wang CS, Xie R, Liu S, Giasson S. Tribological Behavior of Surface-Immobilized Novel Biomimicking Multihierarchical Polymers: The Role of Structure and Surface Attachment. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15592-15604. [PMID: 31550893 DOI: 10.1021/acs.langmuir.9b02018] [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 tribological properties of two novel biomimetic multihierarchical polymers, synthesized by covalently linking single bottlebrush polymers onto a hyaluronic acid (HA) backbone, were investigated in the boundary lubrication regime using the surface forces apparatus. The polymers were immobilized on flat substrates, and their lubrication properties and wear resistance were investigated in aqueous media in the absence of a polymer reservoir (i.e., no free polymer chains in the surrounding medium) in order to better reveal the underlying mechanism of surface-attached biomimetic polymers. The effects of composition, structure, and, more particularly, surface attachment (physisorbed vs chemisorbed) on the tribological properties were investigated and compared with other biomimicking systems reported in the literature. The covalently surface attached bottlebrushes allowed wear resistance between sliding surfaces to be significantly improved, compared to physisorbed bottlebrushes, with a constant coefficient of friction (10-1) of up to few tens of MPa. The results confirm that surface-attached bottlebrushes on their own are not responsible for the extremely low friction often reported in the literature or found in articular joints. Moreover, the study confirmed that the irreversible attachment of bottlebrushes, or multihierarchical polymer layers, to surfaces is crucial to improving wear resistance between sliding surfaces in aqueous media.
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14
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Synergy, competition, and the "hanging" polymer layer: Interactions between a neutral amphiphilic 'tardigrade' comb co-polymer with an anionic surfactant at the air-water interface. J Colloid Interface Sci 2019; 561:181-194. [PMID: 31830734 DOI: 10.1016/j.jcis.2019.11.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 11/03/2019] [Accepted: 11/05/2019] [Indexed: 12/21/2022]
Abstract
Understanding the structure of polymer/surfactant mixtures at the air-water interface is of fundamental importance and also of relevance to a variety of practical applications. Here, the complexation between a neutral 'tardigrade' comb co-polymer (consisting of a hydrophilic polyethylene glycol backbone with hydrophobic polyvinyl acetate grafts, PEG-g-PVAc) with an anionic surfactant (sodium dodecyl sulfate, SDS) at the air-water interface has been studied. Contrast-matched neutron reflectivity (NR) complemented by surface tension measurements allowed elucidation of the interfacial composition and structure of these mixed systems, as well as providing physical insights into the polymer/surfactant interactions at the air-water interface. For both polymer concentrations studied, below and above its critical aggregation concentration, cac, (0.2 cac and 2 cac, corresponding to 0.0002 wt% or 0.013 mM and 0.002 wt% or 0.13 mM respectively), we observed a synergistic cooperative behaviour at low surfactant concentrations with a 1-2 nm mixed interfacial layer; a competitive adsorption behaviour at higher surfactant concentrations was observed where the polymer was depleted from the air-water interface, with an overall interfacial layer thickness ~1.6 nm independent of the polymer concentration. The weakly associated polymer layer "hanging" proximally to the interface, however, played a role in enhancing foam stability, thus was relevant to the detergency efficacy in such polymer/surfactant mixtures in industrial formulations.
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15
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Boundary mode lubrication of articular cartilage with a biomimetic diblock copolymer. Proc Natl Acad Sci U S A 2019; 116:12437-12441. [PMID: 31164421 DOI: 10.1073/pnas.1900716116] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report the design of a diblock copolymer with architecture and function inspired by the lubricating glycoprotein lubricin. This diblock copolymer, synthesized by sequential reversible addition-fragmentation chain-transfer polymerization, consists of a cationic cartilage-binding domain and a brush-lubricating domain. It reduces the coefficient of friction of articular cartilage under boundary mode conditions (0.088 ± 0.039) to a level equivalent to that provided by lubricin (0.093 ± 0.011). Additionally, both the EC50 (0.404 mg/mL) and cartilage-binding time constant (7.19 min) of the polymer are comparable to purified human and recombinant lubricin. Like lubricin, the tribological properties of this polymer are dependent on molecular architecture. When the same monomer composition was evaluated either as an AB diblock copolymer or as a random copolymer, the diblock effectively lubricated cartilage under boundary mode conditions whereas the random copolymer did not. Additionally, the individual polymer blocks did not lubricate independently, and lubrication could be competitively inhibited with an excess of binding domain. This diblock copolymer is an example of a synthetic polymer with lubrication properties equal to lubricin under boundary mode conditions, suggesting its potential utility as a therapy for joint pathologies like osteoarthritis.
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16
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Jiang T, Zajforoushan Moghaddam S, Thormann E. PPEGMEMA-based cationic copolymers designed for layer-by-layer assembly. RSC Adv 2019; 9:26915-26926. [PMID: 35528594 PMCID: PMC9070437 DOI: 10.1039/c9ra05464b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 08/22/2019] [Indexed: 02/04/2023] Open
Abstract
We have synthesized three PPEGMEMA-based cationic copolymers with similar amine contents but with systematic variation in the average length of the PEG side chains. The positively charged copolymers were paired with alginate to fabricate layer-by-layer assembled multilayered films. It was demonstrated that the polymeric design, in terms of the systematic variation in the average length of the PEG units, affects the polyelectrolyte multilayer growth mechanism and can be used to tune the structural properties and the water content of the layers. In addition, by partial cross-linking of the amine groups present in the copolymer backbone, disintegration of the film induced by pH changes was prevented. Finally, it was demonstrated how the cross-linked multilayered film can exhibit cationic, zwitterionic and anionic properties depending on the pH value and how these changes are associated with swelling, layer contraction and changes in water content. PPEGMEMA-based cationic copolymers were synthesized and utilized in a layer-by-layer assembly process to prepare a multilayered film. Film properties were tuned with systematic variation in the average length of the PEG side chains.![]()
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Affiliation(s)
- Tao Jiang
- Department of Chemistry
- Technical University of Denmark
- Denmark
| | | | - Esben Thormann
- Department of Chemistry
- Technical University of Denmark
- Denmark
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17
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Jia W, Tian J, Bai P, Li S, Zeng H, Zhang W, Tian Y. A novel comb-typed poly(oligo(ethylene glycol) methylether acrylate) as an excellent aqueous lubricant. J Colloid Interface Sci 2018; 539:342-350. [PMID: 30594009 DOI: 10.1016/j.jcis.2018.12.085] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 12/22/2018] [Accepted: 12/22/2018] [Indexed: 11/16/2022]
Abstract
HYPOTHESIS Aqueous lubricants exhibit versatile advantages over oil-based lubricants. However, it still remains a challenge for the aqueous solutions to obtain excellent lubrication properties with high contact pressure on macroscale. EXPERIMENTS In this work, a comb-typed poly(oligo(ethylene glycol) methylether acrylate) (P(OEGMA)) was successfully synthesized via RAFT polymerization. Rheological, morphological and tribological properties of prepared P(OEGMA) aqueous solutions were characterized via a rheometer, cryo-SEM and ball-on-disk tribometer, respectively. FINDINGS The synthesized P(OEGMA) exhibited a uniformly smaller size than that of the commercial linear polyethylene glycol (PEG), leading to reduced viscosities in aqueous solutions. The obtained P(OEGMA) aqueous solutions achieved outstandingly ultralow friction coefficients (μ < 0.01) and a good wear-resistance under high pressure (>300 MPa, two-fold increase than reported in the previous literature). The desirable lubricating performances can be attributed to the well-established running-in period, a good interfacial adsorption property between polymer molecules and solid surfaces, the hydration effect as well as the hydrodynamic effect. The current finding reveals the excellent aqueous lubrication properties possessed by the synthesized comb-typed P(OEGMA), which can broaden the development of aqueous lubricants in practical engineering fields.
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Affiliation(s)
- Wenpeng Jia
- State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
| | - Jinmi Tian
- College of Materials Science and Engineering, Qingdao University, Qingdao 266071, China
| | - Pengpeng Bai
- State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
| | - Shaowei Li
- State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Wenling Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
| | - Yu Tian
- State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China.
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18
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Tilton RD. Opportunities for complex fluids engineering
w
ith nanoparticulate polymer brushes. AIChE J 2018. [DOI: 10.1002/aic.16427] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Robert D. Tilton
- Center for Complex Fluids Engineering, Dept. of Chemical Engineering Carnegie Mellon University Pittsburgh Pennsylvania 15213
- Center for Complex Fluids Engineering, Dept. of Biomedical Engineering Carnegie Mellon University Pittsburgh Pennsylvania 15213
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19
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Wu B, Chun BW, Gu L, Kuhl TL. Effect of Ca2+ ion concentration on adsorption of poly(carboxylate ether)-based (PCE) superplasticizer on mica. J Colloid Interface Sci 2018; 527:195-201. [PMID: 29793174 DOI: 10.1016/j.jcis.2018.05.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/08/2018] [Accepted: 05/08/2018] [Indexed: 11/27/2022]
Affiliation(s)
- Bo Wu
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, China; Department of Chemical Engineering and Materials Science, University of California at Davis, Davis, CA 95616, United States
| | - Byong-Wa Chun
- GCP Applied Technologies, Cambridge, MA 02140, United States
| | - Le Gu
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, China
| | - Tonya L Kuhl
- Department of Chemical Engineering and Materials Science, University of California at Davis, Davis, CA 95616, United States.
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20
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Faivre J, Shrestha BR, Xie G, Delair T, David L, Matyjaszewski K, Banquy X. Unraveling the Correlations between Conformation, Lubrication, and Chemical Stability of Bottlebrush Polymers at Interfaces. Biomacromolecules 2017; 18:4002-4010. [DOI: 10.1021/acs.biomac.7b01063] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Jimmy Faivre
- Canada
Research Chair in Bioinspired Materials, Faculty of Pharmacy, Université de Montréal, Montréal, Quebec, Canada
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Ingénierie des Matériaux Polymères
(IMP-UMR 5223), 15 Boulevard
Latarjet, 69622 Villeurbanne Cedex, France
| | - Buddha Ratna Shrestha
- Canada
Research Chair in Bioinspired Materials, Faculty of Pharmacy, Université de Montréal, Montréal, Quebec, Canada
| | - Guojun Xie
- Center
for Macromolecular Engineering, Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Thierry Delair
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Ingénierie des Matériaux Polymères
(IMP-UMR 5223), 15 Boulevard
Latarjet, 69622 Villeurbanne Cedex, France
| | - Laurent David
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Ingénierie des Matériaux Polymères
(IMP-UMR 5223), 15 Boulevard
Latarjet, 69622 Villeurbanne Cedex, France
| | - Krzysztof Matyjaszewski
- Center
for Macromolecular Engineering, Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Xavier Banquy
- Canada
Research Chair in Bioinspired Materials, Faculty of Pharmacy, Université de Montréal, Montréal, Quebec, Canada
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Radzinski SC, Foster JC, Scannelli SJ, Weaver JR, Arrington KJ, Matson JB. Tapered Bottlebrush Polymers: Cone-Shaped Nanostructures by Sequential Addition of Macromonomers. ACS Macro Lett 2017; 6:1175-1179. [PMID: 35650938 DOI: 10.1021/acsmacrolett.7b00724] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Tapered (cone-shaped) bottlebrush polymers were synthesized for the first time by ring-opening metathesis polymerization (ROMP) using a sequential-addition of macromonomers (SAM) strategy. Polystyrene macromonomers with molecular weights that increased from 1 to 10 kg mol-1 were polymerized in sequence to high conversion, yielding tapered bottlebrush polymers that could be visualized by atomic force microscopy (AFM).
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Affiliation(s)
- Scott C. Radzinski
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Jeffrey C. Foster
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Samantha J. Scannelli
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Jeffrey R. Weaver
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Kyle J. Arrington
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - John B. Matson
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
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22
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23
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Andresen Eguiluz RC, Cook SG, Tan M, Brown CN, Pacifici NJ, Samak MS, Bonassar LJ, Putnam D, Gourdon D. Synergistic Interactions of a Synthetic Lubricin-Mimetic with Fibronectin for Enhanced Wear Protection. Front Bioeng Biotechnol 2017; 5:36. [PMID: 28702455 PMCID: PMC5487421 DOI: 10.3389/fbioe.2017.00036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 06/02/2017] [Indexed: 11/25/2022] Open
Abstract
Lubricin (LUB), a major mucinous glycoprotein of mammalian synovial fluids, is believed to provide excellent lubrication to cartilage surfaces. Consequently, when joint disease or replacement leads to increased friction and surface damage in the joint, robust synthetic LUB alternatives that could be used therapeutically to improve lubrication and surface protection are needed. Here, we report the characterization of a lubricating multiblock bottlebrush polymer whose architecture was inspired by LUB, and we investigate the role of fibronectin (FN), a glycoprotein found in the superficial zone of cartilage, in mediating the tribological properties of the polymer upon shear between mica surfaces. Our surface forces apparatus (SFA) normal force measurements indicate that the lubricin-mimetic (mimLUB) could be kept anchored between mica surfaces, even under high contact pressures, when an intermediate layer of FN was present. Additional SFA friction measurements show that FN would also extend the wearless friction regime of the polymer up to pressures of 3.4 MPa while ensuring stable friction coefficients (μ ≈ 0.28). These results demonstrate synergistic interactions between mimLUB and FN in assisting the lubrication and wear protection of ideal (mica) substrates upon shear. Collectively, these findings suggest that our proposed mimLUB might be a promising alternative to LUB, as similar mechanisms could potentially facilitate the interaction between the polymer and cartilage surfaces in articular joints and prosthetic implants in vivo.
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Affiliation(s)
| | - Sierra G Cook
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, United States
| | - Mingchee Tan
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Cory N Brown
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, United States
| | - Noah J Pacifici
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, United States
| | - Mihir S Samak
- Department of Physics, University of Ottawa, Ottawa, ON, Canada
| | - Lawrence J Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - David Putnam
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Delphine Gourdon
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, United States.,Department of Physics, University of Ottawa, Ottawa, ON, Canada
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24
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Ramakrishna SN, Cirelli M, Divandari M, Benetti EM. Effects of Lateral Deformation by Thermoresponsive Polymer Brushes on the Measured Friction Forces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:4164-4171. [PMID: 28394137 DOI: 10.1021/acs.langmuir.7b00217] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The nanotribological properties of hydrophilic polymer brushes are conveniently analyzed by lateral force microscopy (LFM). However, the measurement of friction for highly swollen and relatively thick polymer brushes can be strongly affected by the tendency of the compliant brush to be laterally deformed by the shearing probe. This phenomenon induces a "tilting" in the recorded friction loops, which is generated by the lateral bending and stretching of the grafts. In this study we highlight how the brush lateral deformation mainly affects the friction measurements of swollen PNIPAM brushes (below LCST) when relatively short scanning distances are applied. Under these conditions, the energy dissipation recorded by LFM is almost uniquely determined by stretching and bending of the compliant brush back and forth along the scanning direction, and it is not correlated to dynamic friction between two sliding surfaces. In contrast, when the scanning distance applied during LFM is relevantly longer than the brush lateral deformation, sliding of the probe on the brush interface becomes dominant, and a correct measurement of dynamic friction can be accomplished. By increasing the temperature above the LCST, the PNIPAM brushes undergo dehydration and assume a collapsed morphology, thereby hindering their lateral deformation by scanning probe. Hence, at 40 °C in water the recorded friction loops do not show any tilting and LFM accurately describes the dynamic friction between the probe and the polymer surface.
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Affiliation(s)
- Shivaprakash N Ramakrishna
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich , Vladimir-Prelog-Weg 5/10, 8093 Zurich, Switzerland
| | - Marco Cirelli
- Department of Materials Science and Technology of Polymers, MESA + Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Mohammad Divandari
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich , Vladimir-Prelog-Weg 5/10, 8093 Zurich, Switzerland
| | - Edmondo M Benetti
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich , Vladimir-Prelog-Weg 5/10, 8093 Zurich, Switzerland
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25
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Zuo B, Zhang S, Niu C, Zhou H, Sun S, Wang X. Grafting density dominant glass transition of dry polystyrene brushes. SOFT MATTER 2017; 13:2426-2436. [PMID: 28150841 DOI: 10.1039/c6sm02790c] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The effects of the grafting densities (σp), molecular weights (Mn) and thicknesses of dry polystyrene (PS) brushes on their glass transition temperature (T) were investigated by ellipsometry. The results show that T strongly depends on the grafting density of the PS brushes. The T of the PS brushes with σp > 0.30 increases with decreasing Mn (or brush thickness) and is mainly dominated by entropic effects, in which the grafted chains are highly extended along the film thickness direction resulting in a sharp reduction in configurational entropy. The T of PS brushes with σp < 0.30 decreases with decreasing Mn (or brush thickness) which is mainly dominated by surface effects. For intermediate-density brushes (σp = 0.30), T becomes independent of Mn or brush thickness. The reason for this grafting density dependence of T is attributed to the transition of the PS brush conformation from mushroom-to-brush.
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Affiliation(s)
- Biao Zuo
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Shasha Zhang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Chen Niu
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Hao Zhou
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Shuzheng Sun
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Xinping Wang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
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26
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Faivre J, Shrestha BR, Burdynska J, Xie G, Moldovan F, Delair T, Benayoun S, David L, Matyjaszewski K, Banquy X. Wear Protection without Surface Modification Using a Synergistic Mixture of Molecular Brushes and Linear Polymers. ACS NANO 2017; 11:1762-1769. [PMID: 28071897 DOI: 10.1021/acsnano.6b07678] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We describe the design of lubricating and wear protecting fluids based on mixtures of bottle-brushes (BB) and linear polymer solutions. To illustrate this concept, we used hyaluronic acid (HA), a naturally occurring linear polyelectrolyte, and a water-soluble synthetic BB polymer. Individually, these two polymers exhibit poor wear protecting capabilities compared to that of saline solutions. Mixture of the two polymers in pure water or in saline allows the wear protection of surfaces over a wide range of shearing conditions to drastically increase. We demonstrate that this synergy between the BB and HA polymers emerges from a strong cohesion between the two components forming the boundary film due to entanglements between both polymers. We show that this concept can be applied to other types of linear polymers and surfaces and is independent of the chemical and mechanical properties of the surfaces.
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Affiliation(s)
- Jimmy Faivre
- Canadian Research Chair in Bioinspired Materials, Faculty of Pharmacy, Université de Montréal , Montréal, QC H3T 1J4, Canada
- Université de Lyon, Université Claude Bernard Lyon 1 , CNRS, Ingénierie des Matériaux Polymères (IMP-UMR 5223), 15 Boulevard Latarjet, 69622 Cedex Villeurbanne, France
| | - Buddha R Shrestha
- Canadian Research Chair in Bioinspired Materials, Faculty of Pharmacy, Université de Montréal , Montréal, QC H3T 1J4, Canada
| | - Joanna Burdynska
- Center for Macromolecular Engineering, Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Guojun Xie
- Center for Macromolecular Engineering, Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Florina Moldovan
- Department of Stomatology, Faculty of Dentistry, CHU Sainte Justine Research Center , Montréal QC H3T 1C5, Canada
| | - Thierry Delair
- Université de Lyon, Université Claude Bernard Lyon 1 , CNRS, Ingénierie des Matériaux Polymères (IMP-UMR 5223), 15 Boulevard Latarjet, 69622 Cedex Villeurbanne, France
| | - Stéphane Benayoun
- Laboratoire de Tribologie et Dynamique des Systèmes, UMR 5513 CNRS, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Cedex Ecully, France
| | - Laurent David
- Université de Lyon, Université Claude Bernard Lyon 1 , CNRS, Ingénierie des Matériaux Polymères (IMP-UMR 5223), 15 Boulevard Latarjet, 69622 Cedex Villeurbanne, France
| | - Krzysztof Matyjaszewski
- Center for Macromolecular Engineering, Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Xavier Banquy
- Canadian Research Chair in Bioinspired Materials, Faculty of Pharmacy, Université de Montréal , Montréal, QC H3T 1J4, Canada
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27
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Jing D, Pan Y, Li D, Zhao X, Bhushan B. Effect of Surface Charge on the Nanofriction and Its Velocity Dependence in an Electrolyte Based on Lateral Force Microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:1792-1798. [PMID: 28161957 DOI: 10.1021/acs.langmuir.6b04332] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The nanofriction between a silicon nitride probe and both a silicon wafer and an octadecyltrichlorosilane (OTS)-coated surface is studied in saline solution by using lateral force microscopy (LFM). The effects of surface charge on the nanofriction in an electrolyte as well as its velocity dependence are studied, while the surface charge at the solid-liquid interface is adjusted by changing the pH value of the electrolyte. The results show that the nanofrictional behavior between the probe and the samples in an electrolyte depends strongly on the surface charge at the solid-liquid interface. When the probe and the sample in the electrolyte are charged with the same sign, a repulsive electrostatic interaction between the probe and the sample is produced, leading to a reduction in nanofriction. In contrast, when the two surfaces are charged with the opposite sign, nanofriction is enhanced by the attractive electrostatic interaction between the probe and the sample. The velocity dependence of nanofriction in an electrolyte is believed to be tied to charge regulation referring to a decreasing trend in surface charge densities for the two approaching charged surfaces in an electrolyte. When the probe slides on the sample at a low velocity, charge regulation occurs and weakens the electrostatic interaction between the probe and the sample. As a result, nanofriction is reduced for surfaces charged with the opposite sign, and it is enhanced for surfaces charged with the same sign. When the sliding velocity between the probe and the sample is high, there is insufficient time for charge regulation to occur. Thus, the friction pair shows a larger nanofriction when the surfaces are charged with the opposite sign and a smaller nanofriction when the surfaces are charged with the same sign when compared to the case of a lower sliding velocity.
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Affiliation(s)
- Dalei Jing
- School of Mechanical Engineering, University of Shanghai for Science and Technology , Shanghai 200093, China
| | - Yunlu Pan
- School of Mechanical Engineering, Harbin Institute of Technology , Harbin 150001, China
| | - Dayong Li
- School of Mechanical Engineering, Heilongjiang University of Science and Technology , Harbin 150022, China
| | - Xuezeng Zhao
- School of Mechanical Engineering, Harbin Institute of Technology , Harbin 150001, China
| | - Bharat Bhushan
- School of Mechanical Engineering, Harbin Institute of Technology , Harbin 150001, China
- Nanoprobe Laboratory for Bio/Nanotechnology and Biomimetics (NLB2), The Ohio State University , 201 W. 19th Avenue, Columbus, Ohio 43210-1142, United States
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28
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Briscoe WH. Aqueous boundary lubrication: Molecular mechanisms, design strategy, and terra incognita. Curr Opin Colloid Interface Sci 2017. [DOI: 10.1016/j.cocis.2016.09.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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29
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Gao K, Kearney LT, Howarter JA. Planar Phase Separation of Weak Polyelectrolyte Brushes in Poor Solvent. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/polb.24281] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Kai Gao
- School of Materials Engineering; Purdue University; 701 W Stadium Ave West Lafayette Indiana 47907
| | - Logan T. Kearney
- School of Materials Engineering; Purdue University; 701 W Stadium Ave West Lafayette Indiana 47907
| | - John A. Howarter
- School of Materials Engineering; Purdue University; 701 W Stadium Ave West Lafayette Indiana 47907
- Division of Environmental and Ecological Engineering; Purdue University; 500 Central Dr West Lafayette Indiana 47907
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30
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Abstract
In living organisms the aqueous medium is used for providing low friction forces. This is achieved by synergistic actions of different biomolecules that together accomplish a high load bearing capacity and sustain an easily sheared water layer.
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Affiliation(s)
- Andra Dėdinaitė
- KTH Royal Institute of Technology
- School of Chemical Science and Engineering
- Department of Chemistry
- Division of Surface and Corrosion Science
- Drottning Kristinas väg 51
| | - Per M. Claesson
- KTH Royal Institute of Technology
- School of Chemical Science and Engineering
- Department of Chemistry
- Division of Surface and Corrosion Science
- Drottning Kristinas väg 51
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31
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Guo S, Zhu X, Li M, Shi L, Ong JLT, Jańczewski D, Neoh KG. Parallel Control over Surface Charge and Wettability Using Polyelectrolyte Architecture: Effect on Protein Adsorption and Cell Adhesion. ACS APPLIED MATERIALS & INTERFACES 2016; 8:30552-30563. [PMID: 27762557 DOI: 10.1021/acsami.6b09481] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Surface charge and wettability, the two prominent physical factors governing protein adsorption and cell adhesion, have been extensively investigated in the literature. However, a comparison between these driving forces in terms of their independent and cooperative effects in affecting adhesion is rarely explored on a systematic and quantitative level. Herein, we formulate a protocol that features two-dimensional control over both surface charge and wettability with limited cross-parameter influence. This strategy is implemented by controlling both the polyion charge density in the layer-by-layer (LbL) assembly process and the polyion side-chain chemical structures. The 2D property matrix spans surface isoelectric points ranging from 5 to 9 and water contact angles from 35 to 70°, with other interferential factors (e.g., roughness) eliminated. The interplay between these two surface variables influences protein (bovine serum albumin, lysozyme) adsorption and 3T3 fibroblast cell adhesion. For proteins, we observe the presence of thresholds for surface wettability and electrostatic driving forces necessary to affect adhesion. Beyond these thresholds, the individual effects of electrostatic forces and wettability are observed. For fibroblast, both surface charge and wettability have an effect on its adhesion. The combined effects of positive charge and hydrophilicity lead to the highest cell adhesion, whereas negative charge and hydrophobicity lead to the lowest cell adhesion. Our design strategy can potentially form the basis for studying the distinct behaviors of electrostatic force or wettability driven interfacial phenomena and serve as a reference in future studies assessing protein adsorption and cell adhesion to surfaces with known charge and wettability within the property range studied here.
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Affiliation(s)
- Shanshan Guo
- NUS Graduate School for Integrative Science and Engineering, National University of Singapore , Kent Ridge, Singapore 117576
| | - Xiaoying Zhu
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research , 2 Fusionopolis Way, Singapore 138634
- Department of Environmental Science, Zhejiang University , Hangzhou, China 310058
| | - Min Li
- Department of Chemical & Biomolecular Engineering, National University of Singapore , Kent Ridge, Singapore 119260
| | - Liya Shi
- Department of Chemical & Biomolecular Engineering, National University of Singapore , Kent Ridge, Singapore 119260
| | - June Lay Ting Ong
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research , 2 Fusionopolis Way, Singapore 138634
| | - Dominik Jańczewski
- Laboratory of Technological Processes, Faculty of Chemistry, Warsaw University of Technology , Noakowskiego 3, 00-664 Warsaw, Poland
| | - Koon Gee Neoh
- NUS Graduate School for Integrative Science and Engineering, National University of Singapore , Kent Ridge, Singapore 117576
- Department of Chemical & Biomolecular Engineering, National University of Singapore , Kent Ridge, Singapore 119260
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32
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Riley JK, Tilton RD. Sequential Adsorption of Nanoparticulate Polymer Brushes as a Strategy To Control Adhesion and Friction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:11440-11447. [PMID: 27734683 DOI: 10.1021/acs.langmuir.6b02963] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This work investigates surface forces that result from adsorbed layers of silica nanoparticles with grafted pH-responsive, cationic poly(2-(dimethylamino)ethyl methacrylate) brushes (SiO2-g-PDMAEMA) and how adhesive bridging forces can be suppressed and friction forces reduced by "backfilling" these heterogeneous adsorbed layers with nonionic poly(ethylene oxide) star copolymers (Star PEO45MA). Adsorption of SiO2-g-PDMAEMA and Star PEO45MA to silica is measured as a function of pH by quartz crystal microbalance with dissipation (QCM-D) in order to evaluate the electrostatically driven adsorption of SiO2-g-PDMAEMA and hydrogen-bonding-driven adsorption of Star PEO45MA. Force measurements performed using colloidal probe force microscopy show the strong role that limited surface coverage plays in adhesive bridging forces between silica with adsorbed SiO2-g-PDMAEMA, while Star PEO45MA adsorption produces purely repulsive steric interactions. Bridging between SiO2-g-PDMAEMA-coated surfaces produces frictional forces that tend to be larger than those acting between bare surfaces at similar normal loads, while friction is consistently decreased by Star PEO45MA adsorption. Sequential adsorption of SiO2-g-PDMAEMA and Star PEO45MA generates high-coverage mixed nanoparticulate brush layers with uniformly repulsive normal forces and reduced friction forces. Adsorption and force measurements reveal that Star PEO45MA not only adsorbs to silica but also binds to SiO2-g-PDMAEMA. The latter allows sequential adsorption of the two components to produce mixed multilayers. The mixed SiO2-g-PDMAEMA/Star PEO45MA multilayers exhibit larger layer thicknesses, no bridging, and sustained smooth friction, highlighting their potential usefulness as aqueous boundary lubricant layers.
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Affiliation(s)
- John K Riley
- Center for Complex Fluids Engineering, ‡Department of Chemical Engineering, and §Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Robert D Tilton
- Center for Complex Fluids Engineering, ‡Department of Chemical Engineering, and §Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
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34
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Leuty GM, Tsige M, Grest GS, Rubinstein M. Tension Amplification in Tethered Layers of Bottle-Brush Polymers. Macromolecules 2016; 49:1950-1960. [PMID: 27695137 PMCID: PMC5040463 DOI: 10.1021/acs.macromol.5b02305] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Molecular dynamics simulations of a coarse-grained bead-spring model have been used to study the effects of molecular crowding on the accumulation of tension in the backbone of bottle-brush polymers tethered to a flat substrate. The number of bottle-brushes per unit surface area, Σ, as well as the lengths of the bottle-brush backbones Nbb (50 ≤ Nbb ≤ 200) and side chains Nsc (50 ≤ Nsc ≤ 200) were varied to determine how the dimensions and degree of crowding of bottle-brushes give rise to bond tension amplification along the backbone, especially near the substrate. From these simulations, we have identified three separate regimes of tension. For low Σ, the tension is due solely to intramolecular interactions and is dominated by the side chain repulsion that governs the lateral brush dimensions. With increasing Σ, the interactions between bottle-brush polymers induce compression of the side chains, transmitting increasing tension to the backbone. For large Σ, intermolecular side chain repulsion increases, forcing side chain extension and reorientation in the direction normal to the surface and transmitting considerable tension to the backbone.
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Affiliation(s)
- Gary M. Leuty
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
| | - Mesfin Tsige
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
| | - Gary S. Grest
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Michael Rubinstein
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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35
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Liu G, Cai M, Wang X, Zhou F, Liu W. Magnetite-Loaded Thermosensitive Nanogels for Bioinspired Lubrication and Multimodal Friction Control. ACS Macro Lett 2016; 5:144-148. [PMID: 35668589 DOI: 10.1021/acsmacrolett.5b00860] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ability to control friction is quite attractive for many applications. Other than mechanical/physical methods to control friction, this letter shows how materials chemistry can regulate friction effectively. Magnetite-loaded thermosensitive poly(N-isopropylacrylamide) nanogels (Fe3O4@PNIPAM) were synthesized as nanoparticulate soft matter to reduce friction when it is used as an additive in aqueous lubricant. Interestingly, friction can be multiply regulated by temperature, magnetism, and near-infrared light through manipulating the colloidal properties of multifunctional composite nanogels in bulk solution and at the frictional interface.
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Affiliation(s)
- Guoqiang Liu
- State
Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical
Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Meirong Cai
- State
Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical
Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
| | - Xiaolong Wang
- State
Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical
Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
| | - Feng Zhou
- State
Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical
Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
| | - Weimin Liu
- State
Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical
Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
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36
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Riley JK, An J, Tilton RD. Ionic Surfactant Binding to pH-Responsive Polyelectrolyte Brush-Grafted Nanoparticles in Suspension and on Charged Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:13680-13689. [PMID: 26649483 DOI: 10.1021/acs.langmuir.5b03757] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The interactions between silica nanoparticles grafted with a brush of cationic poly(2-(dimethylamino) ethyl methacrylate) (SiO2-g-PDMAEMA) and anionic surfactant sodium dodecyl sulfate (SDS) is investigated by dynamic light scattering, electrophoretic mobility, quartz crystal microbalance with dissipation, ellipsometry, and atomic force microscopy. SiO2-g-PDMAEMA exhibits pH-dependent charge and size properties which enable the SDS binding to be probed over a range of electrostatic conditions and brush conformations. SDS monomers bind irreversibly to SiO2-g-PDMAEMA at low surfactant concentrations (∼10(-4) M) while exhibiting a pH-dependent threshold above which cooperative, partially reversible SDS binding occurs. At pH 5, SDS binding induces collapse of the highly charged and swollen brush as observed in the bulk by DLS and on surfaces by QCM-D. Similar experiments at pH 9 suggest that SDS binds to the periphery of the weakly charged and deswollen brush and produces SiO2-g-PDMAEMA/SDS complexes with a net negative charge. SiO2-g-PDMAEMA brush collapse and charge neutralization is further confirmed by colloidal probe AFM measurements, where reduced electrosteric repulsions and bridging adhesion are attributed to effects of the bound SDS. Additionally, sequential adsorption schemes with SDS and SiO2-g-PDMAEMA are used to enhance deposition relative to SiO2-g-PDMAEMA direct adsorption on silica. This work shows that the polyelectrolyte brush configuration responds in a more dramatic fashion to SDS than to pH-induced changes in ionization, and this can be exploited to manipulate the structure of adsorbed layers and the corresponding forces of compression and friction between opposing surfaces.
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Affiliation(s)
| | - Junxue An
- KTH Royal Institute of Technology , School of Chemical Science and Engineering, Department of Chemistry, Surface and Corrosion Science, Stockholm SE-100 44, Sweden
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37
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Raftari M, Zhang ZJ, Carter SR, Leggett GJ, Geoghegan M. Nanoscale Contact Mechanics between Two Grafted Polyelectrolyte Surfaces. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b01540] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Maryam Raftari
- Department
of Physics and Astronomy, University of Sheffield, Hounsfield
Road, Sheffield S3 7RH, U.K
| | - Zhenyu J. Zhang
- Department
of Physics and Astronomy, University of Sheffield, Hounsfield
Road, Sheffield S3 7RH, U.K
- Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K
| | - Steven R. Carter
- Department
of Physics and Astronomy, University of Sheffield, Hounsfield
Road, Sheffield S3 7RH, U.K
| | - Graham J. Leggett
- Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K
| | - Mark Geoghegan
- Department
of Physics and Astronomy, University of Sheffield, Hounsfield
Road, Sheffield S3 7RH, U.K
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38
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Yang J, Chen H, Xiao S, Shen M, Chen F, Fan P, Zhong M, Zheng J. Salt-Responsive Zwitterionic Polymer Brushes with Tunable Friction and Antifouling Properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:9125-33. [PMID: 26245712 DOI: 10.1021/acs.langmuir.5b02119] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Development of smart, multifunction materials is challenging but important for many fundamental and industrial applications. Here, we synthesized and characterized zwitterionic poly(3-(1-(4-vinylbenzyl)-1H-imidazol-3-ium-3-yl)propane-1-sulfonate) (polyVBIPS) brushes as ion-responsive smart surfaces via the surface-initiated atom transfer radical polymerization. PolyVBIPS brushes were carefully characterized for their surface morphologies, compositions, wettability, and film thicknesses by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), contact angle, and ellipsometer, respectively. Salt-responsive, switching properties of polyVBIPS brushes on surface hydration, friction, and antifouling properties were further examined and compared both in water and in salt solutions with different salt concentrations and counterion types. Collective data showed that polyVBIPS brushes exhibited reversible surface wettability switching between in water and saturated NaCl solution. PolyVBIPS brushes in water induced the larger protein absorption, higher surface friction, and lower surface hydration than those in salt solutions, exhibiting "anti-polyelectrolyte effect" salt responsive behaviors. At appropriate ionic conditions, polyVBIPs brushes were able to switch to superlow fouling surfaces (<0.3 ng/cm(2) protein adsorption) and superlow friction surfaces (u ∼ 10(-3)). The relationship between brush structure and its salt-responsive performance was also discussed. This work provides new zwitterionic surface-responsive materials with controllable antifouling and friction capabilities for multifunctional applications.
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Affiliation(s)
| | - Hong Chen
- Department of Chemical and Biomolecular Engineering, The University of Akron , Akron, Ohio 44325, United States
| | | | | | | | | | | | - Jie Zheng
- Department of Chemical and Biomolecular Engineering, The University of Akron , Akron, Ohio 44325, United States
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39
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Synthesis and characterization of anionic pentablock brush copolymers bearing poly(acrylic acid) side chains on the brush blocks separated by linear poly(butyl methacrylate) blocks. Eur Polym J 2015. [DOI: 10.1016/j.eurpolymj.2015.02.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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40
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Tairy O, Kampf N, Driver MJ, Armes SP, Klein J. Dense, Highly Hydrated Polymer Brushes via Modified Atom-Transfer-Radical-Polymerization: Structure, Surface Interactions, and Frictional Dissipation. Macromolecules 2014. [DOI: 10.1021/ma5019439] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Odeya Tairy
- Department
of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Nir Kampf
- Department
of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Michael J. Driver
- Vertellus
Biomaterials, Vertellus Specialties UK Ltd., Basingstoke, Hampshire RG25 2PH, U.K
| | - Steven P. Armes
- Department
of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K
| | - Jacob Klein
- Department
of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
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41
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Wang H, Zhang H, Yuan S, Liu C, Xu Z. Molecular dynamics study of the adsorption of anionic surfactant in a nonionic polymer brush. J Mol Model 2014; 20:2267. [PMID: 24831533 DOI: 10.1007/s00894-014-2267-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 04/23/2014] [Indexed: 11/26/2022]
Affiliation(s)
- Hua Wang
- Key Lab of Colloid and Interface Chemistry, Shandong University, Jinan, 250100, China
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42
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Nugroho RWN, Pettersson T, Odelius K, Höglund A, Albertsson AC. Force interactions of nonagglomerating polylactide particles obtained through covalent surface grafting with hydrophilic polymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:8873-8881. [PMID: 23799799 DOI: 10.1021/la401076m] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Nonagglomerating polylactide (PLA) particles with various interaction forces were designed by covalent photografting. PLA particles were surface grafted with hydrophilic poly(acrylic acid) (PAA) or poly(acrylamide) (PAAm), and force interactions were determined using colloidal probe atomic force microscopy. Long-range repulsive interactions were detected in the hydrophilic/hydrophilic systems and in the hydrophobic/hydrophilic PLA/PLA-g-PAAm system. In contrast, attractive interactions were observed in the hydrophobic PLA/PLA and in the hydrophobic/hydrophilic PLA/PLA-g-PAA systems. AFM was also used in the tapping mode to determine the surface roughness of both neat and surface-grafted PLA film substrates. The imaging was performed in the dry state as well as in salt solutions of different concentrations. Differences in surface roughness were identified as conformational changes induced by the altered Debye screening length. To understand the origin of the repulsive force, the AFM force profiles were compared to the Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory and the Alexander de Gennes (AdG) model. The steric repulsion provided by the different grafted hydrophilic polymers is a useful tool to inhibit agglomeration of polymeric particles. This is a key aspect in many applications of polymer particles, for example in drug delivery.
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Affiliation(s)
- Robertus Wahyu N Nugroho
- Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Stockholm, Sweden
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43
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Veeregowda DH, Kolbe A, van der Mei HC, Busscher HJ, Herrmann A, Sharma PK. Recombinant supercharged polypeptides restore and improve biolubrication. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:3426-31. [PMID: 23696056 DOI: 10.1002/adma.201300188] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 03/01/2013] [Indexed: 05/23/2023]
Abstract
Recombinant supercharged polypeptides (SUPs) with low cytotoxicity are developed and applied to rejuvenate the lubrication of naturally occurring salivary conditioning films (SCFs). SUPs with 72 positive charges adsorbed and rigidified the SCFs and recruited mucins to form a hydrated layer. These SCFs with SUPs have higher mechanical strength and sustain lubricating effect for longer duration compared with only SCFs.
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Affiliation(s)
- Deepak H Veeregowda
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, W.J. Kolff Institute, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
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44
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45
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Iarikov DD, Ducker WA. Effect of grafted oligopeptides on friction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:5760-5769. [PMID: 23594080 DOI: 10.1021/la4002225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Frictional and normal forces in aqueous solution at 25 °C were measured between a glass particle and oligopeptide films grafted from a glass plate. Homopeptide molecules consisting of 11 monomers of either glutamine, leucine, glutamic acid, lysine, or phenylalanine and one heteropolymer were each "grafted from" an oxidized silicon wafer using microwave-assisted solid-phase peptide synthesis. The peptide films were characterized using X-ray photoelectron spectroscopy and secondary ion mass spectrometry. Frictional force measurements showed that the oligopeptides increased the magnitude of friction compared to that on a bare hydrophilic silicon wafer but that the friction was a strong function of the nature of the monomer unit. Overall we find that the friction is lower for more hydrophilic films. For example, the most hydrophobic monomer, leucine, exhibited the highest friction whereas the hydrophilic monomer, polyglutamic acid, exhibited the lowest friction at zero load. When the two surfaces had opposite charges, there was a strong attraction, adhesion, and high friction between the surfaces. Friction for all polymers was lower in phosphate-buffered saline than in pure water, which was attributed to lubrication via hydrated salt ions.
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Affiliation(s)
- Dmitri D Iarikov
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24060, United States
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46
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Shahidan NN, Alexander C, Shakesheff KM, Saunders BR. Gelation of microsphere dispersions using a thermally-responsive graft polymer. J Colloid Interface Sci 2013; 396:187-96. [DOI: 10.1016/j.jcis.2013.01.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 01/10/2013] [Accepted: 01/11/2013] [Indexed: 02/09/2023]
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47
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Saigal T, Riley JK, Golas PL, Bodvik R, Claesson PM, Matyjaszewski K, Tilton RD. Poly(ethylene oxide) star polymer adsorption at the silica/aqueous interface and displacement by linear poly(ethylene oxide). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:3999-4007. [PMID: 23448185 DOI: 10.1021/la305085a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Multiarm star copolymers with approximately 460 poly(ethylene oxide) (PEO) arms that have a degree of polymerization N = 45 were synthesized via atom transfer radical polymerization (ATRP) of PEO-methacrylate macromonomers in the presence of divinyl benzene cross-linkers. These are an example of molecular or nanoparticulate brushes that are of interest as steric stabilizers or boundary lubrication agents when adsorbed from solution to a solid/aqueous interface. We use ellipsometry to measure adsorption isotherms at the silica/aqueous interface for PEO star polymers and linear PEO chains having molecular weights comparable either to the star polymer or to the individual arms. The compactness of the PEO star polymers (molecular weight 1.2 × 10(6)) yields a saturation surface excess concentration that is approximately 3.5 times greater than that of the high molecular weight (1 × 10(6)) linear PEO. Adsorption of low molecular weight (6000) linear PEO was below the detection limit. Competitive adsorption experiments were conducted with ellipsometry, complemented by independent quartz crystal microbalance with dissipation (QCM-D) measurements. Linear PEO (high molecular weight) displaced preadsorbed PEO star polymers over the course of approximately 1.5 h, to form a mixed adsorbed layer having not only a significantly lower overall polymer surface excess concentration, but also a significantly greater amount of hydrodynamically entrapped water. Challenging a preadsorbed linear PEO (high molecular weight) layer with PEO star polymers produced no measurable change in the overall polymer surface excess concentration, but changes in the QCM-D energy dissipation and resonance frequency suggested that the introduction of PEO star polymers caused a slight swelling of the layer with a correspondingly small increase in entrapped water content.
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Affiliation(s)
- Trishna Saigal
- Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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48
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Liu X, Dedinaite A, Rutland M, Thormann E, Visnevskij C, Makuska R, Claesson PM. Electrostatically anchored branched brush layers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:15537-15547. [PMID: 23046176 DOI: 10.1021/la3028989] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A novel type of block copolymer has been synthesized. It consists of a linear cationic block and an uncharged bottle-brush block. The nonionic bottle-brush block contains 45 units long poly(ethylene oxide) side chains. This polymer was synthesized with the intention of creating branched brush layers firmly physisorbed to negatively charged surfaces via the cationic block, mimicking the architecture (but not the chemistry) of bottle-brush molecules suggested to be present on the cartilage surface, and contributing to the efficient lubrication of synovial joints. The adsorption properties of the diblock copolymer as well as of the two blocks separately were studied on silica surfaces using quartz crystal microbalance with dissipation monitoring (QCM-D) and optical reflectometry. The adsorption kinetics data highlight that the diblock copolymers initially adsorb preferentially parallel to the surface with both the cationic block and the uncharged bottle-brush block in contact with the surface. However, as the adsorption proceeds, a structural change occurs within the layer, and the PEO bottle-brush block extends toward solution, forming a surface-anchored branched brush layer. As the adsorption plateau is reached, the diblock copolymer layer is 46-48 nm thick, and the water content in the layer is above 90 wt %. The combination of strong electrostatic anchoring and highly hydrated branched brush structures provide strong steric repulsion, low friction forces, and high load bearing capacity. The strong electrostatic anchoring also provides high stability of preadsorbed layers under different ionic strength conditions.
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Affiliation(s)
- Xiaoyan Liu
- Department of Chemistry, Surface and Corrosion Science, School of Chemical Sciences and Engineering, KTH Royal Institute of Technology, Stockholm, Sweden
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49
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Carrillo JMY, Brown WM, Dobrynin AV. Explicit Solvent Simulations of Friction between Brush Layers of Charged and Neutral Bottle-Brush Macromolecules. Macromolecules 2012. [DOI: 10.1021/ma3015849] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jan-Michael Y. Carrillo
- Polymer Program, Institute of
Materials Science and Department of Physics, University of Connecticut, Storrs, Connecticut 06269, United States
| | - W. Michael Brown
- Scientific Computing Department,
National Center for Computational Sciences, Oak Ridge National Laboratories, Oak Ridge, Tennessee 37831, United
States
| | - Andrey V. Dobrynin
- Polymer Program, Institute of
Materials Science and Department of Physics, University of Connecticut, Storrs, Connecticut 06269, United States
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50
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Veeregowda DH, Busscher HJ, Vissink A, Jager DJ, Sharma PK, van der Mei HC. Role of structure and glycosylation of adsorbed protein films in biolubrication. PLoS One 2012; 7:e42600. [PMID: 22916138 PMCID: PMC3419733 DOI: 10.1371/journal.pone.0042600] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 07/10/2012] [Indexed: 12/12/2022] Open
Abstract
Water forms the basis of lubrication in the human body, but is unable to provide sufficient lubrication without additives. The importance of biolubrication becomes evident upon aging and disease, particularly under conditions that affect secretion or composition of body fluids. Insufficient biolubrication, may impede proper speech, mastication and swallowing, underlie excessive friction and wear of articulating cartilage surfaces in hips and knees, cause vaginal dryness, and result in dry, irritated eyes. Currently, our understanding of biolubrication is insufficient to design effective therapeutics to restore biolubrication. Aim of this study was to establish the role of structure and glycosylation of adsorbed protein films in biolubrication, taking the oral cavity as a model and making use of its dynamics with daily perturbations due to different glandular secretions, speech, drinking and eating, and tooth brushing. Using different surface analytical techniques (a quartz crystal microbalance with dissipation monitoring, colloidal probe atomic force microscopy, contact angle measurements and X-ray photo-electron spectroscopy), we demonstrated that adsorbed salivary conditioning films in vitro are more lubricious when their hydrophilicity and degree of glycosylation increase, meanwhile decreasing their structural softness. High-molecular-weight, glycosylated proteins adsorbing in loops and trains, are described as necessary scaffolds impeding removal of water during loading of articulating surfaces. Comparing in vitro and in vivo water contact angles measured intra-orally, these findings were extrapolated to the in vivo situation. Accordingly, lubricating properties of teeth, as perceived in 20 volunteers comprising of equal numbers of male and female subjects, could be related with structural softness and glycosylation of adsorbed protein films on tooth surfaces. Summarizing, biolubrication is due to a combination of structure and glycosylation of adsorbed protein films, providing an important clue to design effective therapeutics to restore biolubrication in patients with insufficient biolubrication.
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Affiliation(s)
- Deepak H. Veeregowda
- Department of Biomedical Engineering, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
| | - Henk J. Busscher
- Department of Biomedical Engineering, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
| | - Arjan Vissink
- Department of Oral Maxillofacial Surgery, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
| | - Derk-Jan Jager
- Department of Oral Maxillofacial Surgery, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
| | - Prashant K. Sharma
- Department of Biomedical Engineering, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
- * E-mail:
| | - Henny C. van der Mei
- Department of Biomedical Engineering, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
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