A Raman spectroscopic study on the hydrogen\|bond defect of water in 2\|hydroxyethyl (meth)acrylate hydrogels crosslinked by ethylene glycol dimethacrylate (EGDMA) and polyethylene glycol dimethacrylates were undertak...A Raman spectroscopic study on the hydrogen\|bond defect of water in 2\|hydroxyethyl (meth)acrylate hydrogels crosslinked by ethylene glycol dimethacrylate (EGDMA) and polyethylene glycol dimethacrylates were undertaken.It was found that PEGDMA 16 possessed a different behavior on the hydrogen\|bond defect from EGDMA and PEGDMA 9.That is,the extents of hydrogen\|bond defect for EGDMA and PEGDMA 9 decreased with the increase of crosslinking density,whereas for PEGDMA 16,as the crosslinking density is bigger than a certain value,the hydrogenbond defect is increased with the increase of crosslinking density.This is caused by the weaker effect of —CH 2OCH 2— in the PEGDMA 16 to the hydrogen\|bond defect of water than that of —OH in HEA and HEMA.展开更多
Atom transfer radical polymerization of protected 2 hydroxyethyl acrylate (HEA\|TMS) was conducted to prepare well\|defined bromo\|terminated macroinitiators,which were further allowed to react with large excess amoun...Atom transfer radical polymerization of protected 2 hydroxyethyl acrylate (HEA\|TMS) was conducted to prepare well\|defined bromo\|terminated macroinitiators,which were further allowed to react with large excess amount of C 60 under ATRP condition.A well defined hammer shaped C 60 PHEA was then obtained by hydrolysis of C 60 PHEA TMS under mild conditions.A TEM observation of the association behavior of these well defined hammer like C 60 PHEA macromolecules showed that they assemble into spherical vesicles in water.Their characteristic inner water phase was further confirmed by fluorescence probe method.Also,it was found that the size of vesicles decreased as the increase of molecular weight of PHEA.展开更多
The hydrogen\|bond defect of water in aqueous solution of a well\|defined poly(2\|hydroxyethyl acrylate)(PHEA) with different molecular weights and concentrations was studied by Raman spectrum analysis. The pre\|desig...The hydrogen\|bond defect of water in aqueous solution of a well\|defined poly(2\|hydroxyethyl acrylate)(PHEA) with different molecular weights and concentrations was studied by Raman spectrum analysis. The pre\|designed molecular weight of PHEAs with narrow polydispersities (<1 20) were synthesized via atom transfer radical polymerization (ATRP). It was found that in a low concentration PHEA aqueous solution(5?wt%), with the increase of molecular weight, the hydrogen bond defect increased markedly, but in a high concentration solution (25?wt%), the hydrogen bond defect was not sensitively affected by the molecular weight of PHEA. At higher temperature, the N value decreased due to the destroying of the hydrogen bond formation between water and the hydrophilic polymer chain in aqueous solutions.展开更多
文摘A Raman spectroscopic study on the hydrogen\|bond defect of water in 2\|hydroxyethyl (meth)acrylate hydrogels crosslinked by ethylene glycol dimethacrylate (EGDMA) and polyethylene glycol dimethacrylates were undertaken.It was found that PEGDMA 16 possessed a different behavior on the hydrogen\|bond defect from EGDMA and PEGDMA 9.That is,the extents of hydrogen\|bond defect for EGDMA and PEGDMA 9 decreased with the increase of crosslinking density,whereas for PEGDMA 16,as the crosslinking density is bigger than a certain value,the hydrogenbond defect is increased with the increase of crosslinking density.This is caused by the weaker effect of —CH 2OCH 2— in the PEGDMA 16 to the hydrogen\|bond defect of water than that of —OH in HEA and HEMA.
文摘Atom transfer radical polymerization of protected 2 hydroxyethyl acrylate (HEA\|TMS) was conducted to prepare well\|defined bromo\|terminated macroinitiators,which were further allowed to react with large excess amount of C 60 under ATRP condition.A well defined hammer shaped C 60 PHEA was then obtained by hydrolysis of C 60 PHEA TMS under mild conditions.A TEM observation of the association behavior of these well defined hammer like C 60 PHEA macromolecules showed that they assemble into spherical vesicles in water.Their characteristic inner water phase was further confirmed by fluorescence probe method.Also,it was found that the size of vesicles decreased as the increase of molecular weight of PHEA.
文摘The hydrogen\|bond defect of water in aqueous solution of a well\|defined poly(2\|hydroxyethyl acrylate)(PHEA) with different molecular weights and concentrations was studied by Raman spectrum analysis. The pre\|designed molecular weight of PHEAs with narrow polydispersities (<1 20) were synthesized via atom transfer radical polymerization (ATRP). It was found that in a low concentration PHEA aqueous solution(5?wt%), with the increase of molecular weight, the hydrogen bond defect increased markedly, but in a high concentration solution (25?wt%), the hydrogen bond defect was not sensitively affected by the molecular weight of PHEA. At higher temperature, the N value decreased due to the destroying of the hydrogen bond formation between water and the hydrophilic polymer chain in aqueous solutions.
