Specific Thermoresponsive Behaviours Exhibited by Optically Active and Inactive Phenylalanine Modifi

• 作 者: Wu-cheng Fang Ran Zhang Ye-feng Yao 刘华姬 陈宇
• 机 构: Tianjin Key Laboratory of Molecular Optoelectronic Science,Department of Chemistry,School of Science
• 出 处: Chinese Journal of Polymer Science
• 发表日期: 2017年08期
• 关键词: inactive optically phenylalanine terminated hydrophobic dilute hydrophilic steps

Optically active and inactive hyperbranched polymers with specific thermoresponsive behaviours in water were reported.Through two steps hyperbranched polyethylenimine(HPEI) polymers terminated with different amount of D-phenylalanine(D-Phe),L-phenylalanine(L-Phe) or DL-phenylalanine(DL-Phe) were prepared and characterized.The analyses on the solution properties by turbidimetry,dynamic light scattering,fluorescence probe and 1H-NMR demonstrated that all the polymers exhibited specific thermoresponsive behaviours in water,including:(1) In the dilute polymer concentration region,increasing the polymer concentration led to the increase of phase transition temperature;(2) The optically inactive thermoresponsive hyperbranched polymers showed a higher cloud-point temperature(Tcp) than their corresponding optically active ones in a relatively higher polymer concentration;(3) At the same polymer concentration the hydrophobic groups of the optically inactive HPEI-DL-Phe formed more perfect hydrophobic domain than those of the optically active HPEI-L-Phe and HPEI-D-Phe.

Optically active and inactive hyperbranched polymers with specific thermoresponsive behaviors in water were reported.Through two steps of hyperbranched polyethylenimine (HPEI) polymers terminated with different amount of D-phenylalanine (D-Phe), L-phenylalanine (L-Phe) or DL-phenylalanine (DL-Phe) were prepared and characterized. The analyzes on the solution properties by turbidimetry, dynamic light scattering, fluorescence probe and 1H-NMR demonstrated that all the polymers tested specific thermoresponsive behaviors in water, including: (1) In the dilute polymer concentration region, increasing the polymer concentration led to the increase of phase transition temperature; (2) The optically inactive thermoresponsive hyperbranched polymers showed a higher cloud-point temperature (Tcp) than their corresponding optically active ones in a relatively higher polymer concentration; (3 At the same polymer concentration the hydrophobic groups of the optically inactive HPEI-DL-Phe formed more perfect hydro phobic domain than those of the optically active HPEI-L-Phe and HPEI-D-Phe.