The role of salt ions and organic molecules in the self-assembled nanolayering

Abstract

This study investigated effects of polyacrylic acid (PAA) on nanolayering self-assembly, and effects of salt ions on the formation of nanolayering after their chemical interaction with 10-methacryloyloxydecyl dihydrogen phosphate (MDP). ACP–MDP suspension was prepared by dispersing 0.01 g ACP nanoparticles in 4 mL of a 5 wt% MDP solution. Then a PAA solution (100 or 500 μg/mL) was mixed into ACP–MDP suspension. The reaction products were analyzed by transmission electron microscope (TEM). After one of the following metal chlorides (each 0.076 mM of CaCl₂, BaCl₂, AlCl₃, FeCl₂, FeCl₃, MnCl₂, CuCl₂, ZnCl₂, or MgCl₂) was dispersed in a 4 mL MDP solution, they were further analyzed by X-ray diffraction (XRD) and TEM. ACP nanoparticles in the MDP solution could self-assemble into ACP–MDP nanolayering composites. The TEM images show that an amount of ACP nanoparticles were aggregated and fused together after the addition of PAA into ACP–MDP suspensions, while no nanolayering was found. The XRD data and TEM images reveal that nanolayering was self-assembled after the chemical interaction of MDP with some metal chlorides (CaCl₂, BaCl₂, AlCl₃, FeCl₂, FeCl₃, MnCl₂), but not with the others (ZnCl₂, CuCl₂, MgCl₂). PAA could inhibit the self-assembly of nanolayering. Some salt ions play an important role in highly ordered, self-assembled nanostructure after their chemical interaction with MDP. The finding is helpful for functional materials fabrication.

Keywords:

• Salts
• PAA
• MDP
• nanolayering
• self-assembly

Acknowledgments

Ling Zhang especially wishes to thank her family, Honglin Zhong, and Lucia Zhong, for their full supports and forever love.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was in part supported by Zhejiang Medical and Health Science and Technology Project [2020367490], Natural Science Foundation of Zhejiang Province, China [LGF20H140009], and National Natural Science Foundation of China [81771120].