An oxetane-derived monomer,3-acryloyloxy-methyl-3p-methyloxetane(AMO)was prepared from the reaction of 3-hydromethyl-3-methyloxetane with acryloyl chloride.The cationic ring-opening copolymerization of AMO with anothe...An oxetane-derived monomer,3-acryloyloxy-methyl-3p-methyloxetane(AMO)was prepared from the reaction of 3-hydromethyl-3-methyloxetane with acryloyl chloride.The cationic ring-opening copolymerization of AMO with another oxetane-derived monomer,3-(2-(2-(2-methoxyethylenoxy)ethylenoxy)ethylenoxy)-3p-methyloxetane(MEMO)was conducted in CH2Cl2 solution using BF3·OEt2/1,4-butanediol as a co-initiator.The resulting copolymers were characterized by FTIR,1H NMR and Gel Permeation Chromatography(GPC)analyses,and it was found that the enchained ratio of AMO in the copolymers is far lower than its feed ratio.They were crosslinked in situ via the radical polymerization of the vinyl group initiated by BPO after doping with lithium trifluoromethanesulfonimide(LiTFSI)to give rise to tough polymeric electrolyte films.The ionic conductivity was measured at varying content of AMO and different concentration of lithium salt LiTFSI by AC impedance,and a maximum ion conductivity of 1.44×10^(−5) S/cm at 30℃ or 1.25×10^(−4) S/cm at 80℃ was attained in the sample PAM 33 at the mole ratio of O:Li=20.The DSC results indicated that Tg decreases with the increase of the proportion of AMO in the copolymer,well consistent with the ion conductivity trend.The TGA(thermo-gravimetric analysis)measurement revealed that this kind of copolymer electrolytes is more thermostable than their liquid counterparts.展开更多
Fmoc or Boc mono-substituted cyclo（L-Lys-L-Lys）s were synthesized via the reaction of lysine cyclic dipeptide with Fmoc N-hydroxysuccinimide este（Fmoc-OSu） and di-tert-butyl dicarbonate[（Boc）20], respectively. T...Fmoc or Boc mono-substituted cyclo（L-Lys-L-Lys）s were synthesized via the reaction of lysine cyclic dipeptide with Fmoc N-hydroxysuccinimide este（Fmoc-OSu） and di-tert-butyl dicarbonate[（Boc）20], respectively. The resulted mono-substituted cyclo（L-Lys-L-Lys）s（2-4） by means of test tube inversion method served as organogelators enabled to form stable thermo-reversible organogels in alcoholic, substituted benzene and chlorinated solvents, with the minimum gelation concentration（MGC） in a range of 1%-4%（mass fraction）. The transmission electron microscopy（TEM） and scanning electron microscopy（SEM） observations reveal that these gelators self-assembled into 3D nanofiber, nanoribbon or nanotube network structures. The rheological measurement exhibited that the sto- rage modulus of gels is higher than the loss one, and the complex viscosity is reduced linearly with the increasing of scanning frequency. The fluorescence spectrum of compound 2 in 1,2-dichloroethane and benzene demonstrates that the emission peak of Fmoc at 320 nm has red-shifted and the intensity decreases gradually, while the intensity of the emission peak at 460 nm substantially enhances as a function of concentration, indicating the existence of π-π stacking interactions and the formation of J-type aggregates. Meanwhile, compound 4 self-assembled into nanotubes via the stacking of multiple bilayer membranes. Fmoc and Boc disubstituted cyclo（L-Lys-L-Lys）（3） holds the relatively lower MGC values, showing the stronger gelation ability in most selected organic solvents due to the presence of both Fmoc and Boc groups.展开更多
基金This research work was supported by the State Key Development Program for Basic Research of China(Grant No.2002CB211800).
文摘An oxetane-derived monomer,3-acryloyloxy-methyl-3p-methyloxetane(AMO)was prepared from the reaction of 3-hydromethyl-3-methyloxetane with acryloyl chloride.The cationic ring-opening copolymerization of AMO with another oxetane-derived monomer,3-(2-(2-(2-methoxyethylenoxy)ethylenoxy)ethylenoxy)-3p-methyloxetane(MEMO)was conducted in CH2Cl2 solution using BF3·OEt2/1,4-butanediol as a co-initiator.The resulting copolymers were characterized by FTIR,1H NMR and Gel Permeation Chromatography(GPC)analyses,and it was found that the enchained ratio of AMO in the copolymers is far lower than its feed ratio.They were crosslinked in situ via the radical polymerization of the vinyl group initiated by BPO after doping with lithium trifluoromethanesulfonimide(LiTFSI)to give rise to tough polymeric electrolyte films.The ionic conductivity was measured at varying content of AMO and different concentration of lithium salt LiTFSI by AC impedance,and a maximum ion conductivity of 1.44×10^(−5) S/cm at 30℃ or 1.25×10^(−4) S/cm at 80℃ was attained in the sample PAM 33 at the mole ratio of O:Li=20.The DSC results indicated that Tg decreases with the increase of the proportion of AMO in the copolymer,well consistent with the ion conductivity trend.The TGA(thermo-gravimetric analysis)measurement revealed that this kind of copolymer electrolytes is more thermostable than their liquid counterparts.
基金Supported by the National Natural Science Foundation of China（No.21174018）.
文摘Fmoc or Boc mono-substituted cyclo（L-Lys-L-Lys）s were synthesized via the reaction of lysine cyclic dipeptide with Fmoc N-hydroxysuccinimide este（Fmoc-OSu） and di-tert-butyl dicarbonate[（Boc）20], respectively. The resulted mono-substituted cyclo（L-Lys-L-Lys）s（2-4） by means of test tube inversion method served as organogelators enabled to form stable thermo-reversible organogels in alcoholic, substituted benzene and chlorinated solvents, with the minimum gelation concentration（MGC） in a range of 1%-4%（mass fraction）. The transmission electron microscopy（TEM） and scanning electron microscopy（SEM） observations reveal that these gelators self-assembled into 3D nanofiber, nanoribbon or nanotube network structures. The rheological measurement exhibited that the sto- rage modulus of gels is higher than the loss one, and the complex viscosity is reduced linearly with the increasing of scanning frequency. The fluorescence spectrum of compound 2 in 1,2-dichloroethane and benzene demonstrates that the emission peak of Fmoc at 320 nm has red-shifted and the intensity decreases gradually, while the intensity of the emission peak at 460 nm substantially enhances as a function of concentration, indicating the existence of π-π stacking interactions and the formation of J-type aggregates. Meanwhile, compound 4 self-assembled into nanotubes via the stacking of multiple bilayer membranes. Fmoc and Boc disubstituted cyclo（L-Lys-L-Lys）（3） holds the relatively lower MGC values, showing the stronger gelation ability in most selected organic solvents due to the presence of both Fmoc and Boc groups.
