Co-reporter:Chenglong Ge;Liang Zhao;Ying Ling
Polymer Chemistry (2010-Present) 2017 vol. 8(Issue 12) pp:1895-1905
Publication Date(Web):2017/03/21
DOI:10.1039/C7PY00170C
Poly(γ-3-methylthiopropyl-L-glutamate) (PMTPLG) with “clickable” thioether groups can be readily prepared from n-butylamine initiated ring-opening polymerization of γ-3-methylthiopropyl-L-glutamic acid based N-carboxyanhydride (MTPLG-NCA). Polypeptides bearing sulfonium moieties and different alkyl (i.e., methyl, n-butyl, and propargyl) pendants were prepared via the alkylation of PMTPLG. They are able to show upper critical solution temperature (UCST)-type thermoresponsive properties in methanol or ethanol depending on the alkyl pendants and counter-anions. Polypeptides bearing sulfonium linkages, ammonium pendants and tetrafluoroborate (BF4−) counter-anions (PPLG-MSEA-BF4) were prepared via the copper-mediated [2 + 3] alkyne–azide 1,3-dipolar cycloaddition of polypeptides bearing sulfonium moieties and propargyl pendants, and subsequently ion-exchange reaction. They showed UCST-type thermo and pH dual responsiveness in aqueous solutions. The sharp solution phase separation of PPLG-MSEA-BF4 occurred in a very small pH range (ΔpH = 0.05) when the pH increased from 7.37 to 7.42 as suggested by dynamic light scattering (DLS). The UCST-type phase transition temperature (Tpt) of PPLG-MSEA-BF4 increased by 20 °C as the pH increased from 7.42 to 7.50 as revealed by variable-temperature UV-vis spectroscopy. Increasing polymer or NaBF4 concentrations or decreasing NaCl concentration can further increase the Tpt.
Co-reporter:Jiang Xiao;Junyan Tan;Rujian Jiang;Xiongliang He;Yanzhi Xu;Ying Ling;Shifang Luan
Polymer Chemistry (2010-Present) 2017 vol. 8(Issue 45) pp:7025-7032
Publication Date(Web):2017/11/21
DOI:10.1039/C7PY01393K
A homopolypeptide, namely poly(S-(2-carboxylethyl)-L-cysteine) (PCELC), with pH and redox dual responsiveness was prepared by ring-opening polymerization of S-(2-(methoxycarbonyl)ethyl)-L-cysteine based N-carboxyanhydride (MCELC-NCA) and subsequent hydrolysis. The pH-induced solution phase transition of PCELC was at pH = ∼4.50 as revealed by DLS and UV-vis spectroscopy. The thioether linkages of PCELC can be readily oxidized by H2O2 at 40 °C yielding PCELCox with sulfoxide and sulfone linkages as revealed by 1H NMR and FTIR. PCELCox also showed pH responsiveness with the variation of polymer aggregation sizes, but without solution phase separation. PCELCox can be partially reduced by 3-mercaptopropionic acid as suggested by 1H NMR and FTIR analysis. The pH-induced solution phase transition behavior of the reduction product (i.e., PCELCre) was different from that of the as-prepared PCELC. Moreover, PCELC can be used as a pH and oxidation dual responsive stabilizer to control the aggregation of single-walled carbon nanotubes (SWCNTs) in aqueous solution.
Co-reporter:Minjie Li, Xiongliang He, Ying Ling, Haoyu Tang
Polymer 2017 Volume 132(Volume 132) pp:
Publication Date(Web):6 December 2017
DOI:10.1016/j.polymer.2017.11.016
•We prepared homopolypeptides with di(ethylene glycol) (DEG) linkages and ionic liquid pendants.•Homopolypeptide bearing DEG and tributylphosphonium iodide groups showed LCST < UCST dual thermoresponsiveness.•Some homopolypeptides showed UCST-type phase behaviors in DI water and/or PBS buffer.Water-soluble homopolypeptides bearing di(ethylene glycol) (DEG) linkages and various ionic liquid (IL) pendants with both lower and upper critical solution temperature (LCST and UCST) or a UCST were prepared and systematically investigated. Poly (γ-2-(2-chloroethoxy)ethyl l-glutamate) (PCEELG) with DEG linkage and reactive chloro groups can be readily prepared from ring-opening polymerization of γ-2-(2-chloroethoxy)ethyl l-glutamic acid based N-carboxyanhydride. Homopolypeptides were conjugated with various IL pendants and counteranions by nucleophilic substitutions and subsequent ion-exchange reactions. Homopolypeptide with DEG linkages and tributylphosphonium iodide (PEELG-TBP-I) showed interesting LCST < UCST (i.e., soluble-insoluble-soluble) dual thermoresponsive behavior in DI-H2O and NaI aqueous solutions. The LCST-type and UCST-type phase transition temperatures (Tpts) were tunable by polymer concentration, molar mass, and NaI concentration. Homopolypeptide with DEG linkages and tributylphosphonium tetrafluoroborate showed a UCST both in DI-H2O and PBS buffer while homopolypeptide with DEG linkages and triphenylphosphonium iodide (or tetrafluoroborate) or with alkyl linkages and tributylphosphonium iodide (or tetrafluoroborate) showed a UCST in PBS buffer. The UCST-type Tpt in PBS buffer was in a broad temperature range of 20–90 °C which was tunable by adjusting the polymer concentration, molar mass, IL moieties, and counteranions.Download high-res image (239KB)Download full-size image
Co-reporter:Minjie Li;Jiang Xiao;Chenglong Ge;Ying Ling
Colloid and Polymer Science 2017 Volume 295( Issue 5) pp:773-782
Publication Date(Web):2017 May
DOI:10.1007/s00396-017-4064-2
A series of glycopolypeptides with constant main-chain lengths and bearing various mannose pendants and 3-methyl-1,2,3-triazolium linkages were synthesized by N-alkylation, ion-exchange reaction, and subsequent deprotection. 1H NMR and FTIR analysis verified their molecular structures. Their solubility and thermoresponsive properties were collectively affected by polymer structure, polymer concentration, and the nature of solvent. Glycopolypeptides bearing tetra-O-acetyl-d-(+)-mannopyranoside and 3-methyl-1,2,3-triazolium chloride linkages showed a reversible upper critical solution temperature (UCST)-type phase behavior in ethanol (EtOH) with a solution phase transition temperature (Tpt) in the range of 39.7–47.4 °C depending on polymer concentration. Glycopolypeptides bearing tetra-O-acetyl-d-(+)-mannopyranoside and 3-methyl-1,2,3-triazolium iodide or 3-methyl-1,2,3-triazolium tetrafluoroborate linkages showed a reversible UCST-type phase behavior in EtOH/H2O solvent mixtures. The Tpt can be adjusted in the range of about 10–50 °C by polymer concentration or the weight percentage of ethanol (fw). It increased as the polymer concentration or fw increased.
Co-reporter:Yanzhi Xu, Mengxiang Zhu, Minjie Li, Ying Ling and Haoyu Tang
Polymer Chemistry 2016 vol. 7(Issue 10) pp:1922-1930
Publication Date(Web):29 Jan 2016
DOI:10.1039/C5PY01991E
Water-soluble thermoresponsive poly(γ-4-methylbenzyl-L-glutamate) bearing Y-shaped (i.e., oligo-ethylene-glycol and alkyl groups, such as 1-butyl, 1-hexyl, or 1-dodecyl) and triazolium tetrafluoroborate side-chains (PMBLG-OEG7/Cm-BF4, m = 4, 6, and 12) have been prepared by nucleophilic substitution of poly(γ-4-methylbenzyl-L-glutamate)-oligo-ethylene-glycol conjugates (PMBLG-OEG7) and various 1-alkyl bromide and ion-exchange reactions of triazolium bromide and NaBF4. Poly(γ-4-chloromethylbenzyl-L-glutamate) (PCMBLG) was derivatized into poly(γ-4-azidomethylbenzyl-L-glutamate) (PAMBLG), followed by reaction with propargyl functionalized polyethylene glycol monomethylether 350 (Pr-OEG7) via a copper-mediated 1,3-dipolar cycloaddition to yield PMBLG-OEG7. PMBLG-OEG7/Cm-BF4, m = 4, 6, and 12) adopted an α-helical conformation and showed lower critical solution temperature (LCST)-type phase behaviors in aqueous solutions. The cloud point temperature (Tcp) was significantly decreased with an increase in polymer concentration and salt (e.g., NaBF4) concentration. Elongating the alkyl chain length can further decrease the Tcp.
Co-reporter:Mengxiang Zhu;Yanzhi Xu;Chenglong Ge;Ying Ling
Journal of Polymer Science Part A: Polymer Chemistry 2016 Volume 54( Issue 10) pp:
Publication Date(Web):
DOI:10.1002/pola.27982
ABSTRACT
A series of OEGylated poly(γ-benzyl-l-glutamate) with different oligo-ethylene-glycol side-chain length, molecular weight (MW = 8.4 × 103 to 13.5 × 104) and narrow molecular weight distribution (PDI = 1.12–1.19) can be readily prepared from triethylamine initiated ring-opening polymerization of OEGylated γ-benzyl-l-glutamic acid based N-carboxyanhydride. FTIR analysis revealed that the polymers adopted α-helical conformation in the solid-state. While they showed poor solubility in water, they exhibited a reversible upper critical solution temperature (UCST)-type phase behavior in various alcoholic organic solvents (i.e., methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, and isopropanol). Variable-temperature UV–vis analysis revealed that the UCST-type transition temperatures (Tpts) of the resulting polymers were highly dependent on the type of solvent, polymer concentration, side- and main-chain length. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1348-1356
Co-reporter:Mengxiang Zhu, Yan Wu, Chenglong Ge, Ying Ling, and Haoyu Tang
Macromolecules 2016 Volume 49(Issue 9) pp:3542-3549
Publication Date(Web):April 26, 2016
DOI:10.1021/acs.macromol.6b00116
Water-soluble random copolypeptides bearing pyridinium tetrafluoroborate (PyBF4) and oligo-ethylene glycol (OEG) pendants (PPLG-PyBF4-r-OEG) showed SO2-induced solution phase transition. They were prepared by sequential postpolymerizations including nucleophilic substitution of poly(γ-3-chloropropyl-l-glutamate) with sodium azide to partially convert chloro groups into azido groups, copper-mediated [2 + 3] alkyne–azide 1,3-dipolar cycloaddition to conjugate OEG pendants, another nucleophilic substitution to conjugate pyridinium chloride, and ion-exchange reaction. FTIR and CD analysis revealed that PPLG-PyBF4-r-OEG samples with suitable molar content of PyBF4 (x ≤ 0.4) were water-soluble and adopted α-helical conformation in both the solid-state and aqueous solution. UV–vis spectroscopy and dynamic light scattering (DLS) results revealed that PPLG-PyBF4-r-OEG aqueous solution underwent a reversible solution phase transition by sequentially bubbling SO2 and N2. 1H NMR analysis suggested that SO2 interacted with triazole groups and induced the solution phase transition.
Co-reporter:Yong Deng;Yanzhi Xu;Xi Wang;Qiulin Yuan;Ying Ling
Macromolecular Rapid Communications 2015 Volume 36( Issue 5) pp:453-458
Publication Date(Web):
DOI:10.1002/marc.201400625
Co-reporter:Qin Hu, Qiulin Yuan, Yong Deng, Ying Ling, Haoyu Tang
European Polymer Journal 2015 Volume 63() pp:74-79
Publication Date(Web):February 2015
DOI:10.1016/j.eurpolymj.2014.12.014
•We prepared thermotropic liquid crystalline polypeptides bearing imidazolium and p-tolyl groups.•We examined the solid-state structures and thermal properties of the resulting polypeptides.•Increasing p-tolyl contents give rise to more stable liquid crystalline phase and higher glass transition temperatures.Polypeptides bearing imidazolium and p-tolyl groups have been synthesized by click chemistry between poly(γ-3-azidopropyl-l-glutamate) (PAPLG) and 3-butyl-1-propargyl imidazolium bromide (BPIB) and 1-methyl-4-prop-2-ynyloxybenzene (MPB). The FTIR results revealed α-helical conformation of all resulting polypeptides in the solid-state. POM and WAXS study revealed that polypeptides with high p-tolyl contents (molar percentage ⩾54%) possessed nematic liquid crystalline phases and hexagonal packing in the solid-state. DSC analysis revealed the solid to liquid crystalline transitions in the temperature range of 35–42 °C.
Co-reporter:Yan Wu, Xi Wang, Ying Ling and Haoyu Tang
RSC Advances 2015 vol. 5(Issue 51) pp:40772-40778
Publication Date(Web):29 Apr 2015
DOI:10.1039/C5RA04541J
Water-soluble polypeptides bearing various pyridinium groups (i.e., pyridinium, 2-methylpyridinium, 3-methylpyridinium, 4-methylpyridinium) and Cl− counter-anions have been prepared by nuleophilic substitutions between poly(γ-3-chloropropyl-L-glutamate) (PCPLG) or poly(γ-6-chlorohexyl-L-glutamate) (PCHLG) and pyridine or y-methyl pyridine (y = 2, 3, and 4). Polypeptides bearing pyridinium groups and BF4− counter-anions were prepared by ion-exchange reactions from the polypeptide–pyridinium conjugates with Cl− counter-anions. CD analysis revealed that water-soluble polypeptides adopted α-helical conformation in solutions with a fractional helicity in the range of 24.7–41.4%. Variable-temperature UV-vis spectroscopy revealed that polypeptides bearing 3-methylpyridinium and BF4− counter-anions (i.e., P11 and P15) showed upper critical solution temperature (UCST)-type transitions in aqueous solutions. The UCST-type phase transition temperatures increased as increasing the hydrophobicity of the spacer groups, the polymer concentrations, and the concentrations of NaBF4.
Co-reporter:Xi Wang, Chenglong Ge, Ying Ling and Haoyu Tang
RSC Advances 2015 vol. 5(Issue 130) pp:108023-108029
Publication Date(Web):15 Dec 2015
DOI:10.1039/C5RA24697K
Glycopolypeptides with different contents of tetra-O-acetyl-D-(+)-mannopyranoside and tetra-O-hydroxyl-D-(+)-mannopyranoside pendants were prepared via copper-mediated [2 + 3] alkyne-azide 1,3-dipolar cycloaddition. Glycopolypeptides with high contents of tetra-O-acetyl-D-(+)-mannopyranoside (x ≥ 44%) exhibited a reversible UCST-type phase behavior in both methanol and ethanol. FTIR analysis revealed that the mechanism of the UCST-type phase behavior originated from the hydrophobic interaction and H-bonding between the polymers and the H-bonding between the polymer and solvent. Variable-temperature UV-vis analysis revealed that the UCST-type transition temperatures (Tpts) of the resulting glycopolypeptides increased as the polymer concentration or main-chain length increased. Incorporation of proton donating groups (i.e., tetra-O-hydroxyl-D-(+)-mannopyranoside) or increasing the number of carbons of aliphatic alcohols led a decrease of maximal concentration and increase of Tpt.
Co-reporter:Qiulin Yuan;Dan Liu;Yong Deng;Ying Ling
Macromolecular Chemistry and Physics 2015 Volume 216( Issue 2) pp:196-204
Publication Date(Web):
DOI:10.1002/macp.201400362
Co-reporter:Dan Liu;Qiulin Yuan;Ying Ling
Macromolecular Chemistry and Physics 2015 Volume 216( Issue 23) pp:2270-2278
Publication Date(Web):
DOI:10.1002/macp.201500260
Co-reporter:Qiu-lin Yuan;Wen-jun Liu;Yong Deng;Ying Ling
Chinese Journal of Polymer Science 2015 Volume 33( Issue 8) pp:1150-1161
Publication Date(Web):2015 August
DOI:10.1007/s10118-015-1665-4
A series of polypeptides bearing biphenyl mesogenic side-chains and oligo-ethylene-glycol (OEG) tails (PPLGn-g-BPOEGm, n = 26 and 63, m = 2, 3, and 7) has been synthesized via a 1,3-dipolar cycloaddition with quantitative grafting density. FTIR results revealed that the polypeptides adopted highly stable α-helix in the temperature range of 25–200 °C. DSC, POM and WAXS analysis revealed that PPLGn-g-BPOEGm (m ≤ 3) samples with short OEG tail length showed two main phase transitions including crystal to liquid crystalline (smectic C, SmC) phase transition and the melting transition of crystalline E-phase, while PPLGn-g-BPOEG7 with longer OEG tail length (m = 7) exhibited the melting transitions without the formation of liquid crystalline phase.
Co-reporter:Yong Deng;Xi Wang;Qiulin Yuan;Mengxiang Zhu;Ying Ling
Journal of Polymer Science Part A: Polymer Chemistry 2015 Volume 53( Issue 21) pp:
Publication Date(Web):
DOI:10.1002/pola.27708
ABSTRACT
A series of side-chain-functionalized α-helical polypeptides, i.e., poly(γ-4-(3-chloropropoxycarbonyl)benzyl-L-glutamate) (6) have been prepared from n-butylamine initiated ring-opening polymerization (ROP) of γ-4-(3-chloropropoxycarbonyl)benzyl-L-glutamic acid-based N-carboxyanhydride. Polypeptides bearing oligo-ethylene-glycol (OEG) groups or 1-butylimidazolium salts were prepared from 6 via copper-mediated [2+3] alkyne-azide 1,3-dipolar cycloaddition or nuleophilic substitution, respectively. CD and FTIR analysis revealed that the polymers adopt α-helical conformations both in solution and the solid state. Polymers bearing OEG (m = 3) side-chains showed reversible LCST-type phase transition behaviors in water while polymers bearing 1-butylimidazolium and I− counter-anions exhibited reversible UCST-type transitions in water. Variable-temperature UV-vis analysis revealed that the phase transition temperatures (Tpts) were dependent on the main-chain length and polymeric concentration. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2469–2480
Co-reporter:Yan Wu;Yong Deng;Qiulin Yuan;Ying Ling
Journal of Applied Polymer Science 2014 Volume 131( Issue 21) pp:
Publication Date(Web):
DOI:10.1002/app.41022
ABSTRACT
A series of thermoresponsive poly(γ-propyl-L-glutamate)-graft-(oligo ethylene glycol)s (PPLG-g-OEGs) with different main-chain and side-chain lengths have been synthesized via copper-mediated alkyne-azide 1,3-dipolar cycloaddition between poly(γ-azidopropyl-L-glutamate)s (PAPLG) and propargyl terminated oligo ethylene glycols (Pr-OEGs). Fourier transform infrared spectrometer analysis revealed that PAPLG10 adopted 39.4% β-sheet, 47.4% α-helix, and 13.2% random coil while PAPLG with longer main-chain length (DP = 37 and 88) and PPLG-g-OEGs adopted exclusive α-helix in the solid state. Circular dichroism analysis revealed that PPLG-g-OEGs adopted α-helical conformations with helicities in the range of 50∼100%. The thermoresponsive behaviors of PPLG-g-OEGs in water have been studied by dynamic light scattering. The polymer concentration, main-/side-chain length, and helicity collectively affected their cloud point temperatures. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41022.
Co-reporter:Haoyu Tang;Ying Ling;Yong Deng;Donghui Zhang
Journal of Polymer Science Part A: Polymer Chemistry 2014 Volume 52( Issue 13) pp:
Publication Date(Web):
DOI:10.1002/pola.27193
Co-reporter:Jiang Xiao, Minjie Li, Wenjun Liu, Yin Li, Ying Ling, Haoyu Tang
European Polymer Journal (March 2017) Volume 88() pp:
Publication Date(Web):March 2017
DOI:10.1016/j.eurpolymj.2017.01.036
•We prepared thermoresponsive l-cysteine or l-glutamate based polypeptides bearing imidazolium pendants.•We examined the molecular structures and thermoresponsive properties of the resulting polypeptides.•l-cysteine based polypeptides are able to show a noticeable UCST-type phase behavior at low critical concentrations.Poly(l-cysteine) bearing imidazolium salts, namely poly(S-(2-(3-(N-butylimidazolium tetrafluoroborate)propoxycarbonyl)ethyl)-l-cysteine) (P(ImBF4)LC) was synthesized by ring-opening polymerization of S-(2-(3-chloropropoxycarbonyl)ethyl)-l-cysteine based N-carboxyanhydride (CPLC-NCA), nucleophilic substitution of poly(S-(2-(3-chloropropoxycarbonyl)ethyl)-l-cysteine) (PCPLC), and subsequent ion-exchange reaction. FTIR and CD analysis revealed the presence of β-sheet conformation of P(ImBF4)LC in the solid-state and aqueous solution, respectively. P(ImBF4)LC with short degree of polymerization (DP = 10) were able to show a distinct upper critical solution temperature (UCST)-type phase behavior at a low critical concentration (1.6 mg mL−1) in water. Variable-temperature UV–vis spectroscopy results revealed that the UCST-type solution phase transition temperature (Tpt) of P(ImBF4)LC in aqueous solutions increased with increasing of polymer concentration or NaBF4 concentration, whereas it decreased by addition of NaI or NaCl.Generally, thermoresponsive ionic liquid (IL)-based polymers require a high critical polymer concentration (Cp ⩾ 2 wt%) to show distinct upper critical solution temperature (UCST)- or lower critical solution temperature (LCST)-type phase behaviors in pure water. Herein, we developed a new type of IL-based polypeptides that showed a distinct UCST-type phase behavior at the lowest critical concentration (Cp = 1.6 mg mL−1) due to its unique solution conformation with the presence of β-sheet and intermolecular H-bonding interaction.Figure optionsDownload full-size imageDownload high-quality image (214 K)Download as PowerPoint slide
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