A facile method to prepare mesoporous polyaniline hollow nanosphere and its application in self-healing coating

In this work, a facile method was developed to prepare mesoporous polyaniline (mPANI) hollow nanospheres using core/shell structured silica nanospheres as substrates. The prepared mPANI hollow nanospheres were composed of external mesoporous PANI shell and internal mesoporous resorcinol-formaldehyde (RF) resin shell. The average diameter, shell thickness, specific area, average pore diameter, and total pore volume of mPANI hollow nanospheres were 330 nm, 78 nm, 75 m(2) g(-1), 6.9 nm, and 0.89 cm(3) g(-1), respectively. 1H-benzotriazole (BTAH) loading rate in mPANI hollow nanospheres was up to 35%. In addition, BTAH can be released from mPANI hollow nanospheres continuously to provide a sustained protection for epoxy coating. Epoxy coating pigmented with 2 wt% mPANI hollow nanospheres loaded with BTAH (mPANI@BTAH) presents remarkable anticorrosion property, and its coating resistance still can be maintained at 10(9) omega cm(2) even after 60-day im-mersion in 3.5 wt% NaCl solution. Furthermore, there are only slight rusts at the scratch after 30-day salt spray test, and the coating adhesion force reduced a little, still up to 6.4 MPa, indicating excellent anticorrosion property. Meanwhile, scanning vibrating electrode technique (SVET) results confirmed that epoxy coating pig-mented with mPANI@BTAH hollow nanospheres exhibited obvious self-healing function. It can be concluded from the series tests that mPANI@BTAH hollow nanospheres as high performance anticorrosion pigments can strongly improve the anticorrosion performance of epoxy coating through combining the passivating function of polyaniline and corrosion inhibition of BTAH together.

Automated summary

A facile method was developed to prepare mesoporous polyaniline (mPANI) hollow nanospheres with excellent anticorrosion property and self-healing function, which can significantly improve the anticorrosion performance of epoxy coating.