Premium
Effect of pH on gelatin self‐association investigated by laser light scattering and atomic force microscopy
Author(s) -
Lin Wei,
Yan Lifeng,
Mu Changdao,
Li Wan,
Zhang Mingrang,
Zhu Qingshi
Publication year - 2002
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.829
Subject(s) - gelatin , biopolymer , isoelectric point , hydrogen bond , chemical physics , intermolecular force , chemistry , macromolecule , hydrophobic effect , atomic force microscopy , ionic strength , ionic bonding , chemical engineering , crystallography , polymer , nanotechnology , molecule , materials science , organic chemistry , aqueous solution , ion , biochemistry , engineering , enzyme
The effect of pH on gelatin self‐association in dilute solution has been investigated for the first time to the authors' knowledge by laser light scattering (LLS) and atomic force microscopy (AFM). It shows that, at the isoelectric point (IEP) of gelatin, the ampholyte macromolecules collapse due to electrostatic attraction forces of oppositely charged groups, and self‐association occurs in turn by an intermolecular association process. The soluble aggregates are stabilized by ionic contacts, hydrogen bonds and hydrophobic interactions, and are protected from precipitation by hydrophilic groups on the surface of the particles. For gelatin‐B away from the IEP, pH ≥ 6.0 or pH ≤ 4.0, the molecular chains behave more like random coils. As expected, the association–disassociation based mainly on electrostatic interactions appears reversible to some certain extent. The experimental results indicate that LLS and AFM, especially a combination of the two, play an important role in obtaining integrated and direct information on the structure and properties of this natural biopolymer. © 2002 Society of Chemical Industry