New composites of waterborne polyurethane （WPU） as a matrix were prepared by incorporating rigid supramolecular nanoplatelets （SNs） as filler, which were self-assembled by the selective inclusion of β-cyclodextr...New composites of waterborne polyurethane （WPU） as a matrix were prepared by incorporating rigid supramolecular nanoplatelets （SNs） as filler, which were self-assembled by the selective inclusion of β-cyclodextrin （β-CD） onto poly（propylene oxide） （PPO） segment in the poly（ethylene oxide）- block-PPO-block-poly（ethylene oxide） （PEO-b-PPO-b-PEO）. It is worth noting that, when the loading level of SN is lower than 3wt%, the SNs with moderate PEO length result in the simultaneous increase in strength, elongation and Young＇s modulus in contrast with neat WPU. If there is no stretching free PEO chain, both strength and elongation decrease in spite of an increase in Young＇s modulus. However, too long PEO chains result in the decrease of mechanical performances while the relatively higher loading-level of SNs also inhibits the enhancement of strength and elongation.展开更多
Ofloxacin is an antibiotic with a wide range of activity against bacterial infections, but due to the high potential for toxicity when exposed to light, resolving this problem and further stabilizing the drug are amon...Ofloxacin is an antibiotic with a wide range of activity against bacterial infections, but due to the high potential for toxicity when exposed to light, resolving this problem and further stabilizing the drug are among the posed challenges. Inclusion complex formation between α-cyclodextrin (α-CD), ofloxacin (OFL) and polyethylene glycol (PEG) was prepared via two methods to produce nanocontainers with desirable stability. The effect of PEG as compatible solubilizing agent and mixing condition (in ultrasonic bath) were investigated in formation of an inclusion complex between α-CD/OFL. Obtained complexes were examined by FTIR, H-NMR, SEM, EDX and UV which indicated the formation of an inclusion complex between α-CD/OFL, in turn, is a mixture of the cage and channel structures. Differences between 1H-NMR, FTIR and XRD spectra of OFL, CDs and inclusion complex indicated the formation of α-CD/OFL and supramolecular containers in solid phase. These inclusion complexes loaded in PVA-based nanofibers for smart nanofibers with controlled release manner and higher stability of OFL. Obtained nanofiber showed that nanofibers containing CDs/OFL under sonic energy containing higher degree of OFL.展开更多
Mono（2-phenylseleno-2-deoxy）-β-cyclodextrin（2） and mono[2-（p-methoxyphenylseleno）-2-deoxy]-β-cyclodextrin（4）, were newly synthesized and characterized by combustion analyses, IR, 1H NMR and 13 C NMR. Spectro...Mono（2-phenylseleno-2-deoxy）-β-cyclodextrin（2） and mono[2-（p-methoxyphenylseleno）-2-deoxy]-β-cyclodextrin（4）, were newly synthesized and characterized by combustion analyses, IR, 1H NMR and 13 C NMR. Spectrofluorometric titrations have been performed in aqueous phosphate buffer solution（pH 7.20, 0.1 mol/L） at 25 ℃ to give the complex K S and -ΔG° for the stoichiometric 1∶1 inclusion complexation of mono（6-phenylseleno-6-deoxy）-β-cyclodextrin（1）, mono[6-（p-methoxyphenylseleno）-6-deoxy]-β-cyclodextrin（3） and the novel cyclodextrin derivatives 2 and 4 with L- and D-tryptophan. The molecular binding ability and selectivity for L- and D-tryptophan of modified β-cyclodextrins（14） are discussed from the size/shape-fit and geometrical complement relationships between the host cavity and the guest molecule. The results obtained indicate that van der Waals force and hydrophobic interactions dominate the complexation of 1—4 and the aromatic substituents introduced extend the original hydrophobicity of cavity and the molecular binding ability, but reduce the enantioselectivity for L/D-tryptophan guests.展开更多
基金Funded by the National Natural Science Foundation of China(20404014and50843031)the Fundamental Research Funds for the Central Universities(Self-Determined and Innovative Research Funds of WUT 2012-Ia-006)
文摘New composites of waterborne polyurethane （WPU） as a matrix were prepared by incorporating rigid supramolecular nanoplatelets （SNs） as filler, which were self-assembled by the selective inclusion of β-cyclodextrin （β-CD） onto poly（propylene oxide） （PPO） segment in the poly（ethylene oxide）- block-PPO-block-poly（ethylene oxide） （PEO-b-PPO-b-PEO）. It is worth noting that, when the loading level of SN is lower than 3wt%, the SNs with moderate PEO length result in the simultaneous increase in strength, elongation and Young＇s modulus in contrast with neat WPU. If there is no stretching free PEO chain, both strength and elongation decrease in spite of an increase in Young＇s modulus. However, too long PEO chains result in the decrease of mechanical performances while the relatively higher loading-level of SNs also inhibits the enhancement of strength and elongation.
文摘Ofloxacin is an antibiotic with a wide range of activity against bacterial infections, but due to the high potential for toxicity when exposed to light, resolving this problem and further stabilizing the drug are among the posed challenges. Inclusion complex formation between α-cyclodextrin (α-CD), ofloxacin (OFL) and polyethylene glycol (PEG) was prepared via two methods to produce nanocontainers with desirable stability. The effect of PEG as compatible solubilizing agent and mixing condition (in ultrasonic bath) were investigated in formation of an inclusion complex between α-CD/OFL. Obtained complexes were examined by FTIR, H-NMR, SEM, EDX and UV which indicated the formation of an inclusion complex between α-CD/OFL, in turn, is a mixture of the cage and channel structures. Differences between 1H-NMR, FTIR and XRD spectra of OFL, CDs and inclusion complex indicated the formation of α-CD/OFL and supramolecular containers in solid phase. These inclusion complexes loaded in PVA-based nanofibers for smart nanofibers with controlled release manner and higher stability of OFL. Obtained nanofiber showed that nanofibers containing CDs/OFL under sonic energy containing higher degree of OFL.
文摘Mono（2-phenylseleno-2-deoxy）-β-cyclodextrin（2） and mono[2-（p-methoxyphenylseleno）-2-deoxy]-β-cyclodextrin（4）, were newly synthesized and characterized by combustion analyses, IR, 1H NMR and 13 C NMR. Spectrofluorometric titrations have been performed in aqueous phosphate buffer solution（pH 7.20, 0.1 mol/L） at 25 ℃ to give the complex K S and -ΔG° for the stoichiometric 1∶1 inclusion complexation of mono（6-phenylseleno-6-deoxy）-β-cyclodextrin（1）, mono[6-（p-methoxyphenylseleno）-6-deoxy]-β-cyclodextrin（3） and the novel cyclodextrin derivatives 2 and 4 with L- and D-tryptophan. The molecular binding ability and selectivity for L- and D-tryptophan of modified β-cyclodextrins（14） are discussed from the size/shape-fit and geometrical complement relationships between the host cavity and the guest molecule. The results obtained indicate that van der Waals force and hydrophobic interactions dominate the complexation of 1—4 and the aromatic substituents introduced extend the original hydrophobicity of cavity and the molecular binding ability, but reduce the enantioselectivity for L/D-tryptophan guests.
