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Xu J, Bai L, Ren W, Zhu H, Zhou X, Zhang C, Wang X. Flattened chains dominate the adsorption dynamics of loosely adsorbed chains on modified planar substrates. SOFT MATTER 2023; 20:201-211. [PMID: 38078383 DOI: 10.1039/d3sm01339a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Herein, the adsorption of polystyrene (PS) on phenyl-modified SiO2-Si substrates was investigated. Different from those for PS adsorption on a neat SiO2-Si substrate, the growth rate (vads) in the linear regime and hads/Rg (hads, thickness of flattened and loosely adsorbed layers on the substrate; Rg, radius of gyration) declined with increasing molecular weight (Mw) of PS and the phenyl content on the modified substrates, while the thickness of the flattened layer (hflat) and its coverage increased with increasing phenyl content. The results indicated that the adsorption of loose chains was controlled by the adsorption of flattened chains, as it only occurred in the empty contact sites remaining after the adsorption of flattened chains. Before approaching quasi-equilibrium (t < tcross), the number of flattened chain contact sites increased due to an enthalpically favorable process and, correspondingly, their spatial positions dynamically changed, which perturbed the adsorption of loose chains. When the adsorption of flattened chains reached quasi-equilibrium (t > tcross), the adsorption of loose chains was determined by the empty contact sites. The coverage of flattened chains and time to reach quasi-equilibrium were increased with more phenyl groups on the substrate, enhancing π-π interfacial interactions and resulting in a decreased adsorption rate and fewer loosely adsorbed chains. Mw-dependent vads and hads/Rg differed on phenyl-modified substrates compared to the neat SiO2-Si substrate owing to fewer empty contact sites for loose chains. The study findings improve our understanding of the mechanism responsible for the formation and structure of the adsorbed layer on solid surfaces.
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Affiliation(s)
- Jianquan Xu
- School of Chemistry and Chemical Engineering, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou, 310018, P. R. China.
| | - Lu Bai
- School of Chemistry and Chemical Engineering, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou, 310018, P. R. China.
| | - Weizhao Ren
- School of Chemistry and Chemical Engineering, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou, 310018, P. R. China.
| | - Huifeng Zhu
- School of Chemistry and Chemical Engineering, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou, 310018, P. R. China.
| | - Xianjing Zhou
- School of Chemistry and Chemical Engineering, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou, 310018, P. R. China.
| | - Cuiyun Zhang
- School of Chemistry and Chemical Engineering, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou, 310018, P. R. China.
| | - Xinping Wang
- School of Chemistry and Chemical Engineering, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou, 310018, P. R. China.
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Xing Z, Zhu N, Yang Y, Wang X, Zuo B. Alternating chain sequence weakening of interfacial molecular interactions enhances the Tg confinement effect of polymers. Polym J 2022. [DOI: 10.1038/s41428-022-00672-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Liu S, Lv M, Li H, Wang S, Feng C, Wang X, Hu W, Wang W. Optical Imaging of the Molecular Mobility of Single Polystyrene Nanospheres. J Am Chem Soc 2022; 144:1267-1273. [PMID: 35014804 DOI: 10.1021/jacs.1c10575] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An ultrathin surface layer with extraordinary molecular mobility has been discovered and intensively investigated on thin-film polymer materials for decades. However, because of the lack of suitable characterization techniques, it remains largely unexplored whether such a surface mobile layer also exists on individual polymeric nanospheres. Here, we propose a thermal-optical imaging technique to determine the glass transition (Tg) and rubber-fluid transition (Tf) temperatures of single isolated polystyrene nanospheres (PSNS) in a high-throughput and nonintrusive manner for the first time. Two distinct steps, corresponding to the glass transition and rubber-fluid transition, respectively, were clearly observed in the optical trace of single PSNS during temperature ramping. Because the transition temperature and size of the same individuals were both determined, single nanoparticle measurements revealed the reduced apparent Tf and increased Tg of single PSNS on the gold substrate with a decreasing radius from 130 to 70 nm. Further experiments revealed that the substrate effect played an important role in the increased Tg. More importantly, a gradual decrease in the optical signal was detected prior to the glass transition, which was consistent with a surface layer with enhanced molecular mobility. Quantitative analysis further revealed the thickness of this layer to be ∼8 nm. This work not only uncovered the existence and thickness of a surface mobile layer in single isolated nanospheres but also demonstrated a general bottom-up strategy to investigate the structure-property relationship of polymeric nanomaterials by correlating the thermal property (Tg and Tf) and structural features (size) at single nanoparticle level.
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Affiliation(s)
- Shasha Liu
- State Key Laboratory of Analytical Chemistry for Life Science, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Mengqi Lv
- State Key Laboratory of Analytical Chemistry for Life Science, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Haoran Li
- State Key Laboratory of Analytical Chemistry for Life Science, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Sa Wang
- State Key Laboratory of Analytical Chemistry for Life Science, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Chengdong Feng
- State Key Lab of Coordination Chemistry, Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Xiaoliang Wang
- State Key Lab of Coordination Chemistry, Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Wenbing Hu
- State Key Lab of Coordination Chemistry, Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Wei Wang
- State Key Laboratory of Analytical Chemistry for Life Science, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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Wang Z, Sun D, Wang X, Yang Y, Li Y, Zuo B, Huang J, Wang X. Enhanced Dynamics of PMMA Brushes Induced by the Chain Ends of a Flexible Polymer Chain. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ziyu Wang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Dandan Sun
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Xin Wang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Yuhui Yang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Yun Li
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Biao Zuo
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Jianhua Huang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Xinping Wang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
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Li Y, Lin D, Xu J, Zhou X, Zuo B, Tsui OKC, Zhang W, Wang X. Glass transition temperature of single-chain polystyrene particles end-grafted to oxide-coated silicon. J Chem Phys 2020; 152:064904. [PMID: 32061204 DOI: 10.1063/1.5140627] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A method based on the PeakForce QNM atomic force microscopic (AFM) adhesion measurement is employed to investigate the glassy dynamics of polystyrene (PS) single-chain particles end-grafted to SiO2-Si substrates with different diameters, D0, of 3.4 nm-8.8 nm and molar masses, Mn, of 8-123 kg/mol. As temperature was increased, the adhesion force, Fad, experienced by the AFM tip on pulling off the single chains after loading demonstrated a stepwise increase at an elevated temperature, which we identified to be Tg based on previous works. Our result shows that Tg of our grafted single chains increases with Mn in a manner consistent with the Fox-Flory equation, but the coefficient quantifying the Mn dependence of Tg is only (36 ± 6)% the value of bulk PS. In addition, the value of Tg in the Mn → ∞ limit is about 25 °C below the bulk Tg but more than 15 °C above that of (untethered) PS nanoparticles with D0 ≈ 100 nm suspended in a solution. Our findings are consistent with Tg of our single chains being dominated by simultaneous effects of the interfaces, which depress Tg, and end-grafting, which enhances Tg. The latter is believed to exert its influence on the glass transition dynamics by a mechanism reliant on chain connectivity and does not vary with chain length.
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Affiliation(s)
- Yawei Li
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Decai Lin
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Jianquan Xu
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Xianjing Zhou
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Biao Zuo
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Ophelia K C Tsui
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Wei Zhang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Xinping Wang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
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Lee JH, Matsumoto H, Fujii S, Takahashi R, Sakurai K. Monodisperse micelles composed of poly(ethylene glycol) attached surfactants: platonic nature in a macromolecular aggregate. SOFT MATTER 2019; 15:5371-5374. [PMID: 31157356 DOI: 10.1039/c9sm00943d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Among the many studies on micelles, dating back more than 100 years, we first found a series of monodisperse micelles: spherical micelles made from calix[4]arene surfactants exhibited monodispersity in aggregation number (Nagg) with values of 4, 6, 8, 12, and 20. We named these Platonic micelles because these values coincided with the face numbers of the Platonic solids. The preferred Nagg values were explained in relation to the mathematical Tammes problem: how to obtain the best coverage of a sphere surface with multiple identical circles. In this paper, we synthesized poly(ethylene glycol)-attached surfactants and carried out small-angle X-ray scattering (SAXS) and analytical ultracentrifugation (AUC) to determine the Nagg. We found that these polymeric surfactants also formed monodispersed micelles and Nagg discontinuously increased from 20 to 24, and then 32 with increasing the alkyl carbon numbers from 9 to 11 continuously. The determined Nagg was greater than 20 and the Platonic solid numbers. We assumed that the preferred Nagg values could be explained in relation to the Tammes problem as well.
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Affiliation(s)
- Ji Ha Lee
- Department of Chemistry and Biochemistry, University of Kitakyushu, 1-1 Hibikino, Kitakyushu, Fukuoka 808-0135, Japan.
| | - Hayata Matsumoto
- Department of Chemistry and Biochemistry, University of Kitakyushu, 1-1 Hibikino, Kitakyushu, Fukuoka 808-0135, Japan.
| | - Shota Fujii
- Department of Chemistry and Biochemistry, University of Kitakyushu, 1-1 Hibikino, Kitakyushu, Fukuoka 808-0135, Japan.
| | - Rintaro Takahashi
- Department of Chemistry and Biochemistry, University of Kitakyushu, 1-1 Hibikino, Kitakyushu, Fukuoka 808-0135, Japan.
| | - Kazuo Sakurai
- Department of Chemistry and Biochemistry, University of Kitakyushu, 1-1 Hibikino, Kitakyushu, Fukuoka 808-0135, Japan.
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