阿拉丁SCI论文搜索工具

MACROMOLECULAR CHEMISTRY AND PHYSICS · 2019 ·Vol. 220 ·期 12 ·1900061 · IF 2.622

Synthesis and Properties of UCST-Type Thermo- and Light-Responsive Homopolypeptides with Azobenzene Spacers and Imidazolium Pendants

Liang Zhao,Lin Zhang,Zelai Zheng,Ying Ling,Haoyu Tang

Homopolypeptide bearing azobenzene and triethylene glycol spacers, and 1-butylimidazolium pendants, namely P(Azo-OEG 3 -ImX) (X = Cl, I, BF 4 ) are prepared by 1,3-dipolar cycloaddition and subsequent ion-exchange reaction. Both 1 H NMR and FTIR confirm the polymer structures and reveal a high grafting efficiency (97%). P(Azo-OEG 3 -ImI) shows reversible upper critical solution temperature (UCST)-type thermoresponsive property in ethanol while P(Azo-OEG 3 -ImI/BF 4 ) shows a UCST in ethanol/water solvent mixtures. P(Azo-OEG 3 -ImI) shows UCST-type phase transitions in ethanol or ethanol/water solvent mixtures. After UV irradiation, the UCST-type cloud point temperature ( T cp ) remains constant in ethanol. However, it decreases after UV irradiation and increases after visible light irradiation in ethanol/water solvent mixtures due to the trans – cis isomerization of azobenzene moieties. P(Azo-OEG 3 -ImCl/I) shows NaI-induced UCST in water. The T cp of the P(Azo-OEG 3 -ImCl/I) aqueous solution is highly related to the polymer/salt concentration and nature of counteranions. P(Azo-OEG 3 -ImCl) also shows reversible light-responsive properties in NaI aqueous solutions. Higher NaI concentration is needed to induce a UCST for P(Azo-OEG 3 -ImCl) after UV irradiation. Moreover, ciprofloxacin-loaded hydrogel containing P(Azo-OEG 3 -ImCl) shows more efficient drug release while the UV irradiation leads to slightly low drug release.

研究领域: 高分子化学 · 材料科学

✓ 已验证 DOI 高影响因子

查看原文查看 PubMed

JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY · 2012 ·Vol. 50 ·期 9 ·1834-1843 · IF 3.919

Synthesis, conformation transition, liquid crystal phase, and self-assembled morphology of thermosensitive homopolypeptide

Ye Liao,Chang-Ming Dong

Thermosensitive diethylene glycol-derived poly( L -glutamate) homopolypeptides (i.e., poly- L -EG 2 -Glu) with different molecular weights (MW) ( M n,GPC = 5380–32520) were synthesized via the ring-opening polymerization (ROP) of EG 2 - L -glutamate N -carboxyanhydride (EG 2 -Glu-NCA) in N , N -dimethylformamide solution at 50 °C. Their molecular structure, conformation transition, liquid crystal (LC) phase behavior, lower critical solution temperature (LCST) transition, and morphology evolution were thoroughly characterized by means of FTIR, 1 H NMR, gel permeation chromatography, differential scanning calorimetry, wide angle X-ray diffraction, polarized optical microscope, transmission electron microscope, and dynamic light scattering. In solid state, the homopolypeptide poly- L -EG 2 -Glu presented a conformation transition from α-helix to β-sheet with increasing their MW at room temperature, while it mainly assumed an α-helix of 80–86% in aqueous solution. Poly- L -EG 2 -Glu showed a thermotropic LC phase with a transition temperature of about 100 °C in solid state, while it gave a reversible LCST transition of 34–36 °C in aqueous solution. The amphiphilic homopolypeptide poly- L -EG 2 -Glu self-assembled into nanostructures in aqueous solution, and their critical aggregation concentrations decreased with increasing MW. Interestingly, their morphology changed from spherical micelles to worm-like micelles, then to fiber micelles with increasing MW. This work provides a simple method for the generation of different nanostructures from a thermosensitive biodegradable homopolypeptide. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

CAS / MDL: 32315-10-9

研究领域: 高分子化学 · 材料科学 · 生物材料

✓ 已验证产品关联 DOI 高影响因子

查看原文查看 PubMed

查找使用阿拉丁产品的科研文献

与阿拉丁产品相关的已发表科研成果

热门产品

Synthesis and Properties of UCST-Type Thermo- and Light-Responsive Homopolypeptides with Azobenzene Spacers and Imidazolium Pendants

Synthesis, conformation transition, liquid crystal phase, and self-assembled morphology of thermosensitive homopolypeptide