Polymers
·
2022
·Vol. 14
·期 9
·1917
·
IF 4.967
Fue Ren,Shuyan Yang,Yang Wu,Feng Guo,Feng Zhou
An ultra-low friction and high load capacity could be obtained on the surfaces grafted by a polymer brush even at relatively slow friction speeds in aqueous lubrication environments, which has attracted widespread attention to study the lubrication mechanism of polymer brushes; however, it has yet to be fully understood. The macroscopic tribological performance of two different polymer brushes, which were prepared by the method of “grafting to” and “grafting from” and named as PLL-g-PEG and PSPMA, respectively, were investigated. The friction results demonstrated that PLL-g-PEG obtained a lower friction coefficient than polymer brush PSPMA, which was ascribed to its unique “self-healing” behavior. The lubrication film was in situ observed and the film thickness induced by the polymer brush was measured using a laboratory set for film thickness measurement apparatus based on interference technology. It was found that PSPMA exhibited excellent lubrication performance not found in PLL-g-PEG, and two film-forming mechanisms highly dependent on velocity were revealed, which may be important to interpret the lubrication mechanism of polymer brushes in aqueous lubricants.Keywords:PLL-g-PEG brushes;PSPMA brushes;friction;film formation property;hydration effect;hydrodynamic effect;lubrication mechanism
研究领域:
摩擦学
·
聚合物科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LANGMUIR
·
2020
·
IF 3.557
Tao Wang,Ran Kou,Jian Zhang,Renwei Zhu,Hongtao Cai,Guangming Liu
In this work, a negatively charged poly(3-sulfopropyl methacrylate potassium) (PSPMA) brush has been employed as a model system to demonstrate the tuning of the light response of strong polyelectrolyte brushes (SPBs) with counterions. The substitution of K+ counterions by azobenzene-containing counterions (Azo-N+) renders the PSPMA brush light-responsive in aqueous solutions. Nevertheless, the strength of the light response of the PSPMA brush is weak due to the inefficient disassembly of the micelle-like aggregates in the brush upon irradiation with ultraviolet light. Counterion mixtures of Azo-N+ and K+ are employed to realize a strong light response of the PSPMA brush by incorporating a reasonable amount of Azo-N+ counterions into the brush. The strength of the light response of the PSPMA brush can be tuned by the mole ratio of Azo-N+ to K+. Furthermore, properties including the hydration and conformation of the PSPMA brush can be reversibly switched via alternating ultraviolet and visible light irradiation. This work opens up the opportunities available for the use of counterions to tune the light response of SPBs.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
LANGMUIR
·
2015
·
IF 4.457
Ran Kou,Jian Zhang,Tao Wang,Guangming Liu
We have investigated the interactions between the positively charged poly[2-(methacryloyloxy)ethyltrimethylammonium chloride] (PMETAC) brushes and the Hofmeister anions and the interactions between the negatively charged poly(3-sulfopropyl methacrylate potassium) (PSPMA) brushes and the Hofmeister cations using a combination of quartz crystal microbalance with dissipation and spectroscopic ellipsometry. A V-shaped anion series is observed in terms of the ion-specific interactions between the PMETAC brushes and the Hofmeister anions. We have found that the chaotropic and kosmotropic anions interact with the PMETAC brushes in different manners. The ion-specific interactions between the PMETAC brushes and the chaotropic anions are dominated by the direct interactions between the anions and the positively charged quaternary ammonium group via ion pairing mediated by ionic hydration strength or polarizability, whereas the ion-specific interactions between the PMETAC brushes and the kosmotropic anions are dominated by the competition for water molecules between the anions and the brushes. The ion-specific interactions between the PMETAC brushes and the anions have significant influences on both the hydration and the conformation of the brushes. The cations exhibit weaker specific ion effects on the PSPMA brushes in comparison with the specific anion effects on the PMETAC brushes.
研究领域:
材料科学
·
生物物理学
✓ 已验证
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2016
·
IF 2.76
Juntao Gu,Shaojun Yuan,Wanting Shu,Wei Jiang,Shengwei Tang,Bin Liang,Simo Olavi Pehkonen
A novel pH-sensitive polystyrene (PS)-type resin was developed by grafting of poly(3-sulfopropyl methacrylate) (PSPMA) brushes onto a cross-linked poly(vinylbenzyl chloride) (PVBC) microsphere via surface-initiated atom transfer radical polymerization (ATRP), and was further utilized as a highly efficient and recyclable sorbent to remove Pb(II) ions from aqueous solutions. The as-synthesized PSPMA-grafted PVBC microspheres were characterized by ATR-FTIR, XPS and SEM. Batch adsorption results revealed that the solution pH had an evident effect on the adsorption capacity of the PSPMA-grafted microspheres towards Pb(II) ions with an optimal sorption pH of above 5.0. The PSPMA-grafted microspheres had rapid adsorption kinetics of Pb(II) ions to reach adsorption equilibrium within 60 min. The Langmuir-fitted adsorption isotherms at pH 5.0 with an initial Pb(II) concentration range of 0.12–0.97 mmol L −1 (i.e. 50–200 mg L −1 ) revealed a maximum capacity of Pb(II) ions of 0.82 mmol g −1 . The calculated thermodynamic parameters demonstrated an endothermic and spontaneous adsorption process of Pb(II) ions on the PSPMA-grafted microspheres. With the inherent stability, high adsorption capacity and good regenerability, the PSPMA-grafted PVBC microsphere resin provides a novel promising PS-type adsorbent for effective removal of heavy metal ions from aqueous solution.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Acta Biomaterialia
·
2022
·
IF 10.633
Yifeng Ni,Dong Zhang,Shuguang Wang,Jingfeng Yuan,Lingbin Che,Dongyong Sha,Md Fauzul Kabir,Si Yu Zheng,Jun Tan,Jintao Yang
Bacteria in the external environment inevitably invade the wound and subsequently colonize the wound surface during surgery and biomedical operations, which slows down the process of wound healing and tissue repair; this poses a significant threat to human health. Therefore, the development of an intelligent antibacterial surface has become the focus of research in the field of antimicrobial strategies, which has important social and economic significance. Here, we present a simple approach of producing an ionic interaction-driven anionic activation substratum which is then functionalized with cationic molecules through coulombic interactional immobilization. The switchable multifunctional antibacterial surface can decrease bacterial attachment and inactivate the attached microorganisms, thus overcoming the conventional challenge for antibacterial surfaces. Briefly, poly (3-sulfopropyl methacrylate potassium salt) (PSPMA) brushes were constructed by surface-initiated atom transfer radical polymerization on silicon or cotton fabric substrates, and a positive-charged component, namely lysozyme (LYZ), hexadecyl trimethyl ammonium bromide (CTAB) or chitosan (CS), was loaded on negative-charged sulfonate groups through electrostatic interactions . The resultant brush-grafted surfaces exhibited more than ∼95.5% bactericidal efficacy and ∼92.8% release rate after the introduction of an adequate amount of contra-ions (1.0 M; Na + & Cl − ) against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus , thus achieving a regenerated surface through the cyclic process of “assembly-dissociation”. Smart cotton fabric (Fabric-PSPMA/LYZ and Fabric-PSPMA/CS) surfaces were constructed, which were found to promote wound epidermal tissue regeneration with a higher efficiency after 7-day in vivo studies. This ionic interaction-driven method used in the present work is simple and can reversibly renew antibacterial surfaces, which will help in the wider utilization of switchable antibacterial materials with a more ecologic and economic significance. Statement of significance Smart antibacterial surfaces with renewable characteristics have attracted considerable interests over the past few years. Here, we used ionic interaction-driven force to manipulate dynamic conformational changes in PSPMA surface brushes, accompanied by highly switchable bacteria killing and bacteria releasing behaviors. Different cationic molecules were also designed for assembly/dissociation on the PSPMA-modified surfaces, and the essential parameters, including chemical structures , molecular weight, and cationic charge density, were investigated. With the refined structural combinations and the balance of bacteria killing/bacteria releasing behaviors, smart cotton fabrics (e.g., Fabric-PSPMA/lysozyme and Fabric-PSPMA/chitosan) were designed that could promote wound healing and tissue repair. These results contribute to the fundamental understanding of a switchable cationic-anionic pair design and the corresponding practical, renewable, highly antibacterial fabric.
研究领域:
材料科学
·
生物医学工程
·
生物材料
·
抗菌技术
·
伤口愈合
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）