Proton exchange membrane(PEM)is an integral component in fuel cells which enables proton transport for efficient energy conversion.Sulfonated Polyether Ether Ketone(SPEEK)has emerged as a cost-effective option with no...Proton exchange membrane(PEM)is an integral component in fuel cells which enables proton transport for efficient energy conversion.Sulfonated Polyether Ether Ketone(SPEEK)has emerged as a cost-effective option with non-fluorinated aromatic backbones for Proton Exchange Membrane Fuel Cell(PEMFC)applications,even though it exhibits lower proton conductivity compared to Nafion.This work aims to study the influence of Sulfonated Chitosan(SCS)concentrations on proton conductivity of SPEEK-based PEM at room temperature.SPEEK was synthesized using a sulfonation process with concentrated sulfuric acid at room temperature.SCS was synthesized via reflux of CS and 1.2 M H2SO4 with a ratio of 1:35(w/v)at 90℃ for 30 min.The composite membranes of SPEEK-SCS were formed with four different SCS concentrations,using the solution castingmethod,andDimethyl Sulfoxide(DMSO)was used as a solvent.The composite membranes synthesized include pure SPEEK(S0),SPEEK with 1%SCS(S1),SPEEK with 2%SCS(S2),and SPEEK with 3%SCS(S3).Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),water uptake,degree of swelling,Ionic exchange capacity(IEC)with Electrochemical impedance spectroscopy(EIS)were used to characterize the composite membranes in terms of composition,crystallinity,water absorption,dimensional changes,number of exchangeable ions in membranes,and proton conductivity,respectively.Notably,S3 had the highest water uptake and the lowest degree of swelling.S2 had the highest proton conductivity among the SPEEK-SCS composite membranes at room temperature with 3.44×10^(−2) Scm^(-1).展开更多
Chitosan(CS), a kind of naturally produced polysaccharide with extraordinary biocompatibility and biodegradation, shows much potential to act as reducing and stabilizing agent in the synthesis of gold nanoparticles(Au...Chitosan(CS), a kind of naturally produced polysaccharide with extraordinary biocompatibility and biodegradation, shows much potential to act as reducing and stabilizing agent in the synthesis of gold nanoparticles(AuNPs) for drug delivery. To solve the poor solubility and expand the pharmaceutical applications of CS, various CS derivatives through rational design have been developed and further used to prepare, stabilize, and mediate self-assembling of gold materials. Herein, we chose sulfonic chitosan as a stabilizing reagent for the synthesis of highly stable AuNPs(AuNP/SCSs) with diameters of about 3 nm. For investigating their surface electronic payload of charged drugs, the negatively charged fluorescence isothiocyanate(FITC) and positively charged Rhodamine B(Rb) were used as models to be modified on the surface of the AuNP/SCSs via a layer-by-layer(Lb L) method. With a basis of the fluorescence resonance energy transfer(FRET) principle, via adjusting the distance between AuNPs and fluorescent molecules by tuning the layers of charged polymers, the regulation of the fluorescence intensity of the fluorescent molecules has been achieved. In addition, the drug loading efficiency was investigated.展开更多
文摘Proton exchange membrane(PEM)is an integral component in fuel cells which enables proton transport for efficient energy conversion.Sulfonated Polyether Ether Ketone(SPEEK)has emerged as a cost-effective option with non-fluorinated aromatic backbones for Proton Exchange Membrane Fuel Cell(PEMFC)applications,even though it exhibits lower proton conductivity compared to Nafion.This work aims to study the influence of Sulfonated Chitosan(SCS)concentrations on proton conductivity of SPEEK-based PEM at room temperature.SPEEK was synthesized using a sulfonation process with concentrated sulfuric acid at room temperature.SCS was synthesized via reflux of CS and 1.2 M H2SO4 with a ratio of 1:35(w/v)at 90℃ for 30 min.The composite membranes of SPEEK-SCS were formed with four different SCS concentrations,using the solution castingmethod,andDimethyl Sulfoxide(DMSO)was used as a solvent.The composite membranes synthesized include pure SPEEK(S0),SPEEK with 1%SCS(S1),SPEEK with 2%SCS(S2),and SPEEK with 3%SCS(S3).Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),water uptake,degree of swelling,Ionic exchange capacity(IEC)with Electrochemical impedance spectroscopy(EIS)were used to characterize the composite membranes in terms of composition,crystallinity,water absorption,dimensional changes,number of exchangeable ions in membranes,and proton conductivity,respectively.Notably,S3 had the highest water uptake and the lowest degree of swelling.S2 had the highest proton conductivity among the SPEEK-SCS composite membranes at room temperature with 3.44×10^(−2) Scm^(-1).
基金supported by the National Natural Science Foundation of China (30900337, 31470916, 81673390)Jiangsu Provincial Natural Science Foundation (BK20150689)+2 种基金the Fundamental Research Funds for the Central Universities (2015PT036)the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Open Project Program of MOE Key Laboratory of Drug Quality Control and Pharmacovigilance (DQCP2015MS01)
文摘Chitosan(CS), a kind of naturally produced polysaccharide with extraordinary biocompatibility and biodegradation, shows much potential to act as reducing and stabilizing agent in the synthesis of gold nanoparticles(AuNPs) for drug delivery. To solve the poor solubility and expand the pharmaceutical applications of CS, various CS derivatives through rational design have been developed and further used to prepare, stabilize, and mediate self-assembling of gold materials. Herein, we chose sulfonic chitosan as a stabilizing reagent for the synthesis of highly stable AuNPs(AuNP/SCSs) with diameters of about 3 nm. For investigating their surface electronic payload of charged drugs, the negatively charged fluorescence isothiocyanate(FITC) and positively charged Rhodamine B(Rb) were used as models to be modified on the surface of the AuNP/SCSs via a layer-by-layer(Lb L) method. With a basis of the fluorescence resonance energy transfer(FRET) principle, via adjusting the distance between AuNPs and fluorescent molecules by tuning the layers of charged polymers, the regulation of the fluorescence intensity of the fluorescent molecules has been achieved. In addition, the drug loading efficiency was investigated.
