Aggregation Behavior Of Styrene-maleic Acid Copolymer In Aqueous Solution Investigated By Fluorescence Spectra

Styrene-maleic acid copolymer (SMA) is one kind of amphiphilic polymers as molecular chain of SMA consists of both hydrophobic Styrene segment and hydrophilic Maleic acid segment. SMA copolymer with a low molecular weight has good ability of dispersion, chelate, flocculation, emulsifying etc in Aqueous Solution. In recent years, it has been extensive concerned by the academic and industrial sector, and has been a good application in light industry, environmental protection industry etc, particularly as water treating agent involved metal ions. However, the application for low concentration metal ions of SMA is rarely reported in aqueous systems.This work the steady-state fluorescence spectra and resonance scattering spectra based on Fluorescence Spectrometer were utilized to study aggregation behavior of styrene-maleic acid copolymer in aqueous systems with low concentration metal ions in order to provide the basis for the application of SMA in aqueous systems with low concentration of metal ions.The main contents and conclusions of this paper are as follows:(1)We synthesized seris of styrene-maleic amphiphilic copolymer with different proportion of maleic anhydride.We investigated the characteristics of their fluorescence by Fluorescence Spectrometry and effect of amount of maleic anhydride on fluorescence of styrene-maleic alternating copolymers.We found that fluorescence emission spectra and excitation spectra of SMA showed good chiral symmetry.Besides, their emission spectra relied on excitation length and concention. With the decreasing of maleic anhydride, the intensity of fluorescence at 362nm increased and appeared red shifts.We investigated solutions of styrene-maleic copolymer with different structure by fluorescence spectrometry, finding styrene-maleic copolymer with different structure had different peak positions and peak shapes. Compared to the alternating copolymer, fluorescence spectrometry of random copolymer undergone significant red shift and symmetry of peak shape became deteriorated.(2) we investigated effect of Al3+、Fe3+、Cu2+、Ca2+、Na+ solutions with low concentration on aggregation behavior of molecular chain of SMA by steady fluorescence spectrometry.Without addition of probe and marker, intrinsic fluorescence of Benzene on molecular chain of SMA revealed that single metal ion and multiple metal ion induced aggregation of SMA molecular. The results indicated that interaction between metal ions and molecular chain of SMA included electrostatic interaction, ionomer interaction and coordinated interaction. The interaction could induce molecular chain of SMA to shrink and curl gradually. After that aggregation behavior of molecular chain of SMA appeared and formed spherical aggregation lastly, which triggered separation of microscopic phase.(3) we investigated effect of Al3+、Fe34+、Cu2+、Pb2+、Ca2+、Zn2+、Na+ solutions with low concentration on aggregation behavior of molecular chain of SMA by resonance scattering spectrometry based on fluorescence spectrometry. The results showed that when concentrations of Al3+、Fe3+、Cu2+、Pb2+、Ca2+、Zn2+、Na+ below a certain value, Resonance scattering spectrometry of SMA remain stable.Molecular chain of SMA shrank and curled gradually and even aggregated slightly. When concentrations of Al3+、Fe3+、Cu2+、Pb2+、Ca2+、Zn2+、Na+ above a certain value, intensity of resonance scattering increased significantly. Molecular chain of SMA and metal ion formed micelles and aggregation. It further generated aggregation of large dimensions. Even molecular chain of styrene-maleic acid copolymer may collapse to form spherical aggregation, which triggered separation of microscopic phase. Based on the results of experiments, our work also proposed the way of interaction between SMA and metal ions and explained reason for increasing intensity of Resonance scattering. It also proposed aggregation behavior of molecular chain of SMA with the appearance of Al3+、Fe3+ Cu2+、Pb2+、Ca2+、Zn2+、Na+ solutions at low concentration.(4)The research indicated that on researching the aggregation behavior of styrene-maleic acid copolymer induced by metal ions with low concentration, resonance scattering spectrometry had more advantages than steady-state fluorescence spectroscopy. The advantages are as follows:resonance scattering spectrometry could explain the principles of the aggregation behavior of styrene-maleic acid copolymer induced by metal ions with low concentration; resonance scattering spectrometry could explain the aggregation behavior of styrene-maleic acid copolymer induced by metal ions with low concentration more sensitively and accurately. It had strong resistance to interference and good reproducibility. For some ions, for example Fe3+, steady-state fluorescence spectroscopy couldn’t reflect aggregation behavior of styrene-maleic acid copolymer induced by metal ions with low concentration completely, but resonance scattering spectrometry could reflect aggregation behavior of styrene-maleic acid copolymer induced by metal ions with low concentration completely.