Thermodynamic properties of aqueous polymer solutions: poly(ethylene glycol)/dextran

1989 ◽  
Vol 93 (14) ◽  
pp. 5612-5617 ◽  
Author(s):  
C. A. Haynes ◽  
R. A. Beynon ◽  
R. S. King ◽  
H. W. Blanch ◽  
J. M. Prausnitz
Keyword(s):  
Thermodynamic Properties ◽  
Ethylene Glycol ◽  
Polymer Solutions ◽  
Poly Ethylene Glycol ◽  
Aqueous Polymer ◽  
Poly Ethylene

scholarly journals Alpha-beta transition induced by C18-conjugation of polyalanine and its implication in aqueous solution behavior of poly(ethylene glycol)-polyalanine block copolymers

2020 ◽  
Vol 24 (1) ◽  
Author(s):  
Min Hee Park ◽  
Jinkyung Park ◽  
Hyun Jung Lee ◽  
Byeongmoon Jeong
Keyword(s):  
Aqueous Solution ◽  
Block Copolymers ◽  
Ethylene Glycol ◽  
Polymer Solutions ◽  
Poly Ethylene Glycol ◽  
Solution Behavior ◽  
Aqueous Polymer ◽  
Poly Ethylene ◽  
Α Helix ◽  
Β Sheet

Abstract Background The aqueous solution behavior of thermosensitive PEG-PA block copolymers as well as secondary structure of PA is expected to significantly change through modification of the hydrophobic PA by long chain alkyl (C18) groups with different configurations. Method Oleoyl and stearoyl (C18) groups were conjugated to poly(ethylene glycol)-poly(L-alanine) (PEG-PA; EG45A16) diblock copolymers to compare their conjugation effect on nano-assemblies and corresponding aqueous solution behavior of the polymers. Results Due to the nature of a hydrophilic PEG block and a hydrophobic PA or C18-modified PA, PEG-PA, oleoyl group-conjugated PEG-PA (PEG-PAO), and stearoyl group-conjugated PEG-PA (PEG-PAS) block copolymers form micelles in water. Compared with PEG-PA, the micelle size of PEG-PAO and PEG-PAS increased. Circular dichroism and FTIR spectra of aqueous polymer solutions showed that β sheet content increased, whereas α helix content decreased by C18 modification of PEG-PA. PEG-PAS showed better performance in ice crystallization inhibition than PEG-PAO. The sol-to-gel transition temperatures of aqueous PEG-PAO solutions were 25–37 °C higher than those of aqueous PEG-PA solutions, whereas aqueous PEG-PAS solutions remained as gels in the temperature range of 0–80 °C. 1H-NMR spectra indicated that the oleoyl groups increased core mobility, whereas stearoyl groups decreased the core mobility of the micelles in water. The difference in micromobility between PAO and PAS interfered or promoted gelation of the aqueous polymer solutions, respectively. Conclusions This study suggests that a hydrophobic C18-modification of polypeptide induces α helix-to-β sheet transition of the polypeptide; however, aqueous solution behaviors including ice recrystallization inhibition and gelation are significantly affected by the nature of the hydrophobic molecule. Graphical abstract

Molar mass fractionation in aqueous two-phase polymer solutions of dextran and poly(ethylene glycol)

2016 ◽  
Vol 1452 ◽  
pp. 107-115 ◽  
Author(s):  
Ziliang Zhao ◽  
Qi Li ◽  
Xiangling Ji ◽  
Rumiana Dimova ◽  
Reinhard Lipowsky ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Molar Mass ◽  
Polymer Solutions ◽  
Poly Ethylene Glycol ◽  
Two Phase ◽  
Mass Fractionation ◽  
Poly Ethylene
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