Research On The Construction And Application Of Functional Colloidal Materials Based On Melamine Resin Microspheres

Composite microspheres have attracted more and more researchers' attention because of their chemical composition and structure with the increasing demand for materials.Compared with single component microspheres,composite microspheres not only have the function of single phase,but also have the additional characteristics of all components and higher integration function,which widens their application field.This paper based on the melamine-formaldehyde microspheres(MF),several kinds of functional colloidal materials were built.First,melamine-formaldehyde colloid microspheres were successfully prepared by condensation polymerization of melamine and paraformaldehyde in aqueous media.By means of rich functional groups,MF/Ag composite microspheres were formed in situ reduction.And then,MF/Ag composite microspheres array was prepared by self-assembly arrangement of MF microspheres in gas/liquid interfaces.After hydrophobic treatment,the SERS performance of superhydrophobic MF/Ag composite microspheres array was explored.At the same time,the polydimethylsiloxane(PDMS)was used to seal and protect one portion of the MF microspheres.On the one hand,the exposed portion was modified to prepare MF Janus particles with different components,and on the other hand the exposed surface was etched to obtain the MF non-spherical particles with single portion.The research contents of this paper are as follows:(1)Monodispersed MF microspheres were prepared by condensation polymerization of melamine and paraformaldehyde with sulphuric acid(pH = 3.5)as catalyst.Without any reducing agent or auxiliary agent,MF microspheres served as the active template and was reduced to MF/Ag composite microspheres in situ in silver precursors[Ag(Nh3)2]+ ions just by abundant functional groups of themselves.These as-synthesized MF/Ag composite microspheres were used as the antibacterial materials to explore antibacterial activity against both Escherichia coli(E.coli,Gram-negative bacteria)and Staphylococcus aureus(S.aureus,Gram-positive bacteria)as well.Furthermore,the MF/Ag composite microspheres were served as the active substrates of surface-enhanced Raman scattering(SERS)for the trace detection organic compounds(e.g.4-aminobenzenethiol and penicillin G sodium)to evaluate the applicability for drug residue detection in the environment.(2)A single-layer ordered MF microspheres array was self-assemble in the gas/liquid interface and transferred from the gas/liquid interface to the PDMS surface.Then the MF microspheres array was added into the Tollens' reagent to obtain the MF/Ag composite microspheres array and used 1H,1H,2H,2H-perfluorodecyl mercaptan for superhydrophobic treatment.The SERS enhanced performance and stability of superhydrophobic MF/Ag composite microspheres array was evaluated as SERS active substrate by detection of neurotransmitters(dopamine).Finally,the substrate was used in detection of two macromolecular proteins(lysozyme and hemoglobin)to explore the application prospect of protein detection.(3)By topological selection surface modification method,a portion of the single-layer MF microspheres was trapped and protected by PDMS.On the one hand,the exposed portion was modified.The PDMS were added in silver ammonia solution,the Tris-HCl solution of dopamine,the ethanol solution of tetraethyl orthosilicate(TEOS)and ammonia solution,respectively,and MF/Ag Janus particles,MF/PDA Janus particles and MF/SiO2 Janus particles were obtained.On the other hand,the exposed portion was etched by acid to obtain the MF non-spherical particles and explore the influence of etching time and acid concentration to the morphology and size of MF non-spherical particles.