Polymeric micelles were prepared by dropping ethanol into solutions containing（poly（γ-benzyl L-）glutamate）-poly（ethylene oxide） block copolymer （PBLG-b-PEO）,chloroform（CHCl3） and trifluoroacetic acid（TFA）...Polymeric micelles were prepared by dropping ethanol into solutions containing（poly（γ-benzyl L-）glutamate）-poly（ethylene oxide） block copolymer （PBLG-b-PEO）,chloroform（CHCl3） and trifluoroacetic acid（TFA）.Viscometry,transmission electron microscopy（TEM）,nuclear magnetic resonance（（）1H-NMR） spectroscopy and infra-red difference spectroscopy（IR） were used to investigate the influence of PBLG chain conformation on the self-assembly behavior of PBLG-b-PEO.The experimental results revealed that PBLG-b-PEO could associate into polymeric micelles in ethanol solutions.The introduction of TFA not only changes the conformation of PBLG segments,but also increases the critical micelle concentration,and further affects the morphologies of the formed micelles.展开更多
Self-association behavior of an amphiphilic polypeptide graft copolymer,poly(γ-benzyl L-glutamate)-g-poly(ethylene glycol), and the drug carrier capability of the formed micelles were examined by fluorescence spectro...Self-association behavior of an amphiphilic polypeptide graft copolymer,poly(γ-benzyl L-glutamate)-g-poly(ethylene glycol), and the drug carrier capability of the formed micelles were examined by fluorescence spectroscopy,transmission electron microscopy and UV spectroscopy.It was found that the hydrophobic inner core of the micelles formed by poly(γbenzyl L-glutamate)(PBLG) segments can act as an incorporation site for hydrophobic drugs.The drug-loading content of the graft copolymer micelles tends to be larger when the content of the PBLG segments in the copolymer increases.The results obtained from the drug-release studies showed that the drug-release rates were dependent on the chemical nature of the graft copolymer.展开更多
Phase transitions of polymer liquid crystals may be i nduced not only by changes of temperature or polymer concentration,but also b y external electric,magnetic or other orientational fields.In this paper the pha se b...Phase transitions of polymer liquid crystals may be i nduced not only by changes of temperature or polymer concentration,but also b y external electric,magnetic or other orientational fields.In this paper the pha se behavior of polypeptide liquid crystal solutions,such as PBLG/TCE and PBLG/CH Cl 3/TFA solutions,was studied in the presence of an external electric field.It was found that the liquid crystal phase was stabilized when the external electr ical field was applied and the area of liquid crystal phase was broadened.Qualit atively,the experimental results are in good agreement with the theoretical resu lts calculated by a lattice model previously.The information obtained may be use d to develop new routes for processing rigid flexible block copolymers with be tter mechanical properties and to construct molecular devices for processing and storing information.展开更多
文摘Polymeric micelles were prepared by dropping ethanol into solutions containing（poly（γ-benzyl L-）glutamate）-poly（ethylene oxide） block copolymer （PBLG-b-PEO）,chloroform（CHCl3） and trifluoroacetic acid（TFA）.Viscometry,transmission electron microscopy（TEM）,nuclear magnetic resonance（（）1H-NMR） spectroscopy and infra-red difference spectroscopy（IR） were used to investigate the influence of PBLG chain conformation on the self-assembly behavior of PBLG-b-PEO.The experimental results revealed that PBLG-b-PEO could associate into polymeric micelles in ethanol solutions.The introduction of TFA not only changes the conformation of PBLG segments,but also increases the critical micelle concentration,and further affects the morphologies of the formed micelles.
文摘Self-association behavior of an amphiphilic polypeptide graft copolymer,poly(γ-benzyl L-glutamate)-g-poly(ethylene glycol), and the drug carrier capability of the formed micelles were examined by fluorescence spectroscopy,transmission electron microscopy and UV spectroscopy.It was found that the hydrophobic inner core of the micelles formed by poly(γbenzyl L-glutamate)(PBLG) segments can act as an incorporation site for hydrophobic drugs.The drug-loading content of the graft copolymer micelles tends to be larger when the content of the PBLG segments in the copolymer increases.The results obtained from the drug-release studies showed that the drug-release rates were dependent on the chemical nature of the graft copolymer.
文摘Phase transitions of polymer liquid crystals may be i nduced not only by changes of temperature or polymer concentration,but also b y external electric,magnetic or other orientational fields.In this paper the pha se behavior of polypeptide liquid crystal solutions,such as PBLG/TCE and PBLG/CH Cl 3/TFA solutions,was studied in the presence of an external electric field.It was found that the liquid crystal phase was stabilized when the external electr ical field was applied and the area of liquid crystal phase was broadened.Qualit atively,the experimental results are in good agreement with the theoretical resu lts calculated by a lattice model previously.The information obtained may be use d to develop new routes for processing rigid flexible block copolymers with be tter mechanical properties and to construct molecular devices for processing and storing information.
