An efficient strategy has been developed to reconstruct chain folding and traversing of poly(L-lactide)(PLLA)during melt crystallization based on the selective hydrolysis of its amorphous regions.The molecular weights...An efficient strategy has been developed to reconstruct chain folding and traversing of poly(L-lactide)(PLLA)during melt crystallization based on the selective hydrolysis of its amorphous regions.The molecular weights of the pristine PLLA(crystalline part),single stem,and single cluster were determined by gel permeation chromatography(GPC)according to their evolution during alkali hydrolysis.The maximum-folding-number(in a single cluster)and minimum-cluster-number(in one polymer chain)were obtained using these molecular weights.With the help of two numbers,the chain folding and traversing during the melt crystallization process(at 120℃)of PLLA can be described as follows.Statistically,in a single polymer chain,there are at least 2 clusters consisting of up to 6.5 stems in each of them,while the rest of the polymer chain contributes to amorphous regions.Our results provide a new strategy for the investigation and fundamental understanding of the melt crystallization of PLLA.展开更多
A tri-quaternary ammonium salt cationic surfactant was synthesized.Its structure was confirmed by using Fourier-transform infrared spectroscopy,^(1)H nuclear magnetic resonance spectroscopy,and X-ray photoelectron spe...A tri-quaternary ammonium salt cationic surfactant was synthesized.Its structure was confirmed by using Fourier-transform infrared spectroscopy,^(1)H nuclear magnetic resonance spectroscopy,and X-ray photoelectron spectroscopy analyses.Three model surfaces,including Au-CH_(3),Au-OH and Au-COOH,were fabricated.Adsorptions of surfactant on the three model surfaces and subsequent plasma proteins adsorption were investigated by quartz crystal microbalance with dissipation(QCM-D).The mass of surfactant on the Au-COOH surface was the largest,followed by that on the Au-CH_(3)surface,and that on the Au-OH surface.These results suggested that the main driving force of surfactant immobilization was electrostatic interaction followed by hydrophobic interaction.Based on the results obtained,we concluded that the protein mass adsorbed on Au-CH_(3)-S,Au-OH-S,and Au-COOH-S surfaces depended on the protein size and orientation.The mass and thickness of S on the Au-COOH surface is the largest and the protein adsorption capacity of Au-COOH-S surface is inferior to that of Au-CH_(3)-S.The Au-COOH-S surface could inhibit lysozyme adsorption,maintain the adsorption balance of bovine serum albumin,and induce fibrinogen-binding protein adsorption.展开更多
基金financially supported by"Pioneer"and"Leading Goose"R&D Program of Zhejiang(No.2023C03130)the National Natural Science Foundation of China(No.22373029)+1 种基金Interdisciplinary Research Project of Hangzhou Normal University(No.2024JCXK02)Open Project Program of Key Laboratory of Yarn Materials Forming and Composite Processing Technology of Zhejiang Province(No.MTC2022-09)。
文摘An efficient strategy has been developed to reconstruct chain folding and traversing of poly(L-lactide)(PLLA)during melt crystallization based on the selective hydrolysis of its amorphous regions.The molecular weights of the pristine PLLA(crystalline part),single stem,and single cluster were determined by gel permeation chromatography(GPC)according to their evolution during alkali hydrolysis.The maximum-folding-number(in a single cluster)and minimum-cluster-number(in one polymer chain)were obtained using these molecular weights.With the help of two numbers,the chain folding and traversing during the melt crystallization process(at 120℃)of PLLA can be described as follows.Statistically,in a single polymer chain,there are at least 2 clusters consisting of up to 6.5 stems in each of them,while the rest of the polymer chain contributes to amorphous regions.Our results provide a new strategy for the investigation and fundamental understanding of the melt crystallization of PLLA.
基金the National Natural Science Fundamental Committee of China and HI-Tech Research and the Development Program(863,No.2006AA02Z291)of China.
文摘A tri-quaternary ammonium salt cationic surfactant was synthesized.Its structure was confirmed by using Fourier-transform infrared spectroscopy,^(1)H nuclear magnetic resonance spectroscopy,and X-ray photoelectron spectroscopy analyses.Three model surfaces,including Au-CH_(3),Au-OH and Au-COOH,were fabricated.Adsorptions of surfactant on the three model surfaces and subsequent plasma proteins adsorption were investigated by quartz crystal microbalance with dissipation(QCM-D).The mass of surfactant on the Au-COOH surface was the largest,followed by that on the Au-CH_(3)surface,and that on the Au-OH surface.These results suggested that the main driving force of surfactant immobilization was electrostatic interaction followed by hydrophobic interaction.Based on the results obtained,we concluded that the protein mass adsorbed on Au-CH_(3)-S,Au-OH-S,and Au-COOH-S surfaces depended on the protein size and orientation.The mass and thickness of S on the Au-COOH surface is the largest and the protein adsorption capacity of Au-COOH-S surface is inferior to that of Au-CH_(3)-S.The Au-COOH-S surface could inhibit lysozyme adsorption,maintain the adsorption balance of bovine serum albumin,and induce fibrinogen-binding protein adsorption.
