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30 results on '"Lu, Man-geng"'

2. Temperature-responsiveness and sustained delivery properties of macroporous PEG-co-PNIPAAm-co-PCL hydrogels

Author

Li, Zhao-Xia, Lu, Man-Geng, Wu, Kun, Zhang, Yun-Fei, Miao, Lei, Li, Yin-Wen, Guo, Hui-Long, and Zheng, Jian

Subjects
Calorimetry -- Methods, Polyethylene glycol -- Usage, Colloids -- Chemical properties -- Thermal properties -- Production processes -- Identification and classification, Chemical synthesis -- Methods, Engineering and manufacturing industries, Science and technology
Abstract

A series of novel thermosensitive macroporous poly (ethylene glycol) (PEG)-co-poly(N-isopropylacrylamide) (PNIPAAm)-co-poly (ζ-caprolactone) (PCL) hydrogels were synthesized via in situ free radical polymerization. Polyethylene glycol diacrylate) (PEGDAc) and poly(r:-caprolactone diacrylate) (PCLDAc) were prepared as macrocrosslinkers. All compounds were investigated by Nuclear Magnetic Resonance (NMR) and Fourier transform-infrared spectroscopy (FT-IR). Differential Scanning Calorimetry (DSC) results showed the lower critical solution temperatures (LCSTs) of the gels were at around 31°C. The macroporous gels not only had considerable swelling ratios, but also exhibited rapid swelling kinetics and response sensitivity. Above mentioned hydrogels showed a remarkable oscillatory swelling-deswelling transition, making them have potential application in long-term drug delivery., INTRODUCTION Stimuli-responsive hydrogels [1, 2] which attracted substantial attention and have been widely investigated over the past few decades due to their smart response to external stimuli such as temperature, [...]

Published
2015
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10. Synthesis and characterization of thermo-sensitive poly (N-isopropylacrylamide) hydrogel with fast response rate

Author

LU Man-geng, Liu Qun-feng, Qin Ai-xiang, and Zhang Ping

Subjects
Materials science, Aqueous solution, Scanning electron microscope, technology, industry, and agriculture, Analytical chemistry, macromolecular substances, General Chemistry, complex mixtures, Lower critical solution temperature, chemistry.chemical_compound, Differential scanning calorimetry, chemistry, Chemical engineering, Self-healing hydrogels, Poly(N-isopropylacrylamide), medicine, Cellulose, Swelling, medicine.symptom
Abstract

Thermo-sensitive poly (N-isopropylacrylamide) (PNIPA) hydrogel with fast response rate was prepared by polymerizing N-isopropylacrylamide (NIPA) in an aqueous hydroxyl-propyl-methyl cellulose solution. The volume phase transition temperature of PNIPA hydrogels was characterized by differential scanning calorimetry (DSC), and the surface morphology was observed by scanning electron microscopy (SEM). The swelling ratios of the hydrogels at different temperatures were measured. Furthermore, the deswelling kinetics of the hydrogels was also studied by measuring their water retention capacity. In comparison with a conventional PNIPA hydrogel prepared in water, the hydrogel synthesized in aqueous hydroxyl-propyl-methyl cellulose solution has higher swelling ratios at temperatures below the lower critical solution temperature and exhibits a much faster response rate to temperature changes. For example, the hydrogel made in aqueous hydroxyl-propyl-methyl cellulose solution lost 89% water within 1 min and about 93% water in 4 min, whereas the conventional hydrogel lost only about 66% water in 15 min from the deswelling measurement in similar conditions.

Published
2007

30. Synthesis and Photophysics of Two Dipolar Copolymers Containing Hole-Transporting Unit and Alq3 Unit

Author

Luo, Jian Xin, Liang, Li Yan, and Lu, Man Geng

Abstract

Two novel copolymers combining the electron-transporting group (Alq3), hole-transporting group (carbazole and phenothiazine) and chromophore had been obtained. The copolymers were characterized by 1H NMR, IR and UV-vis absorption spectrum, and exhibited good solubility in a wide range of organic solvents such as toluene, THF, chloroform, DMF and DMSO. GPC shows moderate molecular masses of the copolymers around 15000 and a narrower weight distribution (PDI≈1.4). The DSC and TGA measurements indicated that the resulting copolymers have excellent thermal stability and higher glass transition temperatures than the commonly used light-emitting conjugated polymers. The PL properties of the copolymers were investigated in solution and in the solid state. Only the Alq3 emission (520 nm) was observed at high concentration (10 g/L) or in solid state. However, with the decrease in concentration of the copolymer solution, the characteristic emission of carbazole appears. This means the energy transfer taken place in higher concentration is more efficient than in lower concentration solution.

Published
2010
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