| At present, people are increasingly seeking for a clean living environment. But at the same time we face widespread AIDS and other diseases, as well as the increasing drug-resistant microorganisms. Therefore, design and synthesis of novel antibacterial agents with high efficiency, long-lasting, low toxicity effect become a urgent research focus in functional material field, especially in terms of antimicrobial treatment of medical protective clothing, nurse uniform, surgical masks, and underwear.Polysiloxane is one of the most popular finishing agents with low surface tension and good film-forming capacity. When coated and anchored on hydrophilic fabric surfaces, polysiloxanes not only modify the surface properties of the treated substrates greatly, but also could provide the treated fabrics with softness, smoothness, and diversified tactile.Therefore, the bactericidal quaternary ammonium group was introduced into the polysiloxanes by the principle of molecular design and chemical reactions. A series of novel quaternary ammonium functionalized(silsesquioxane) polysiloxanes and the hybrid polymers were firstly designed and synthesized. Relevant properties of the synthesized quaternary ammonium functionalized(silsesquioxane) polysiloxanes and the hybrid polymers were investigated. And the antibacterial activities of the polymers were especially discussed. All the polymers were applied in the textile finishing, and also their micro-morphology and chemical compositions on the cotton surface as well as the applied properties were researched in depth. Besides, three kinds of superpolysiloxanes were self-assembled from quaternary ammonium functionalized polysiloxane and carboxyl modified polysiloxane based on electrostatic interaction in isopropanol solution. Also micro-morphology, chemical compositions and performance properties of the superpolysiloxanes were discussed. The main research contents are listed as following:(1) A series of novel polysiloxanes(QPEPS-1 ~ QPEPS-13) bearing long-chain alkyl quaternary ammonium polyether groups were synthesized by the reactions of epoxy polyether polysiloxanes, which were prepared from polymethylhydrosiloxane(PHMS) and allyl epoxy compound(AEP) via hydrosilylation, with N,N-dimethylalkylamine(DMLA). Chemical structures and properties of the synthesized QPEPSs and the emulsions were characterized by fourier transform infrared spectrum(FT-IR) and nuclear magnetic resonance spectrum(1H-NMR), transmission electron microscopy(TEM), field emission scanning electron microscopy(FESEM), surface tensiometer, rotational viscometer, particle size analyzer and Zeta potential analyzer, and microplate reader. Moreover, the co-relationship among structure, morphology and antibacterial activity was especially studied by inhibition zone test and the minimum inhibitory concentration(MIC) test. And the antibacterial mechanism was also elucidated. The results shows that like the other polysiloxanes in nature, QPEPSs are still low surface tension materials and of surface tensions about 18.66~ 21.19 m N/m. Under the influence of the quaternary ammonium polyether groups, the QPEPSs are easily emulsified into a clear, uniform micro-emulsion with a mean size of about 24~69nm. The Zeta potentials of the QPEPS micro-emulsions are among +22.8m V~+47.6m V. And the QPEPS have good compatibility with non-ionic and cationic resins or auxiliaries. The results of antibacterial test show the QPEPS can diffuse through the cell wall and disrupt the cytoplasmic membrane to release cell constituents, which causes bacterial cell death. QPEPSs display excellent antibacterial activities against both Staphylococcus aureus and Escherichia coli. The minimum inhibitory concentrations(MICs) of QPEPSs are among 0.31~1.25mg/m L against both S. aureus and E. coli. And the number of quaternary ammonium group and the long-chain alkyl in quaternary ammonium group could obviously affect the antibacterial activity of QPEPS against both S. aureus and E. coli. The more the number of quaternary ammonium groups are, the better the antibacterial activity is. Meanwhile, the shorter the long-chain alkyl(R=C12H25, C14H29, C16H33, C18H37) in quaternary ammonium group is, the better the antibacterial activity is. Besides, the antibacterial activity of QPEPSs is stronger against S. aureus than that against E. coli.Then QPEPSs were coated and anchored on the cotton fabric and oxidized silicon wafer. Film morphology, Chemical compositions and performance of the treated fabrics were investigated by FESEM, atomic force microscopy(AFM), X-ray photoelectron spectroscopy(XPS), energy disperse spectroscopy(EDS), contact angle goniometer(CA), flexibility tester, whiteness meter, and so on. FESEM and AFM show the QPEPS forms a macroscopic smooth but actually microscopic rugged film on the treated substrate surface. There were many pinnacles-likes scattered on the treated wafer surface. The root mean square roughness(Rq) of the QPEPS-4 film reaches 0.615 nm in 2μm×2μm scanning field. And the largest height of the pinnacles achieved 7.618 nm. The pinnacles in the QPEPS AFM image maybe result from the upstanding aggregates of long alkyl quaternary ammonium polyether groups in the polysiloxane side chains. Characteristic structure and rugged film morphology make QPEPS easily exhibiting a soft, fluffy, and comfortable tactile on the treated fabrics and providing the fabrics with wettability, whiteness, and antibacterial activity. And the more the number of quaternary ammonium groups and polyether groups are, the better the wettability is. QPEPS-4 can confer fabrics with wettability of about 1.73 s. The QPEPS-4 can decrease the bending rigidity(BR) of the treated fabrics from 1049 m N(w) and 424 m N(f) before treatment(the control) to 618 m N(w) and 290 m N(f) after treatment. And the whiteness for the treated fabrics changes little and is very near to that of the untreated fabric. Besides, the cotton fabrics treated by QPEPSs demonstrates the ability to eliminate up to 99% of both S. aureus and E. coli. And the treated fabrics can still eliminate up to 97% of S. aureus and 95% of E. coli after washing 20 times.(2) A novel antibacterial quaternary ammonium-functionalized silicon resin(QRS-1) was synthesized by the reaction of epoxy group silicon resin, which were prepared from hydrogen silicon resin(HRS) and allyl glycidyl ether(AGE) via hydrosilylation, with dimethyl long chain alkyl tertiary amine(DMLA). The tetramethylclotetrasiloxane(D4H) or triethoxysilane(TES) was also used as precursor. The same preparation method with QRS-1 was implemented to prepare antibacterial long alkyl chain quaternary ammonium functionalized cyclotetrasiloxane(QRS-2) and long alkyl chain quaternary ammonium functionalized triethoxysilane(QTS), respectively. Then QRS-1 and QRS-2 were separately blocked or grafted into the main chain or side chain of polysiloxane. And the antibacterial quaternary ammonium functionalized silicon resin block polyether amino polysiloxane(QRPS-1) and polyorganosiloxane(QRPS-2) with pendant quaternary ammonium functionalized cyclotetrasiloxane were synthesized. In addition, quaternary ammonium functionalized polysilsesquioxane oligomers(QRS-3) were prepared by hydrolysiscondensation reaction of antibacterial QTS. Then QRS-3 was used in the silicone rubber coating, and the hybrid silicone rubber(QRPS-3) was prepared. The chemical structures, micro-morphology and performance of the intermediates and the final products were characterized by FT-IR, 1H-NMR, FESEM, AFM, XPS, EDS, flexibility tester, whiteness meter, and so on.The results show that the wafer surface treated by QRS-1 has many peaks-like protrusions. The Rq reaches 0.255 nm in 1μm×1μm scanning field. The peaks-like protrusions in the AFM image are estimated to result from the aggregates of dodecyl quaternary ammonium groups in the QRS-1. There are many hills-like scattered on the wafer surface treated by QRS-2. The Rq achieves 3.91 nm in 2μm×2μm scanning field. The hills in the AFM image may be produced by the aggregates of dodecyl quaternary ammonium groups in the QRS-2 or a number of QRS-2. And QRPS-1 and QRPS-2 both can form a macroscopic uniform polysiloxane films on the treated fabric surface. QRS-3 is nanoscale particles. And the hybrid silicone rubber QRPS-3 can form a rubber film uniformly embedding with QRS-3 on the treated fabric surface. Therefore, the QPRSs all can significantly improve the adhesions of the QRS on the fabric surface and the handle of treated fabrics.The antibacterial test results indicate that QRS-1, QRS-2 and QTS all show outstanding antibacterial activities against both S. aureus and E. coli. The fabrics treated by QRPS-1 and QRPS-2 also both display excellent antibacterial activities against both S. aureus and E. coli. After washing 20 times, QRPS-1 and QRPS-2 could still eliminate up to 95% and 90% of both S. aureus and E. coli, respectively. And QRPS-3 also show certain bactericidal activity against S. aureus and E. coli.(3) A carboxyl terminated polyether polysiloxane(CPS-2) was synthesized by the reaction of maleic anhydride(MAn) with polyether amino terminated polydimethylsiloxane(BPEAS). The chemical structure and morphology of the CPS-2 were characterized by FT-IR, 1H-NMR, FESEM and AFM. FESEM photos show that the CPS-2 forms a macroscopic smooth film on the treated fiber surface. However, there are many small bright rings on the surface of CPS-2 film in the AFM images. The bright rings are estimated to be produced by the curl and aggregate of CPES micelles, while the inner of the ring is estimated to result from the polysiloxane segment of CPS-2. The Rq of the CPS-2 film reaches 0.652 nm in 2μm×2μm scanning field.Then, by means of QPEPS and QRS-2 as cationic architecture subunits, and by using side chain carboxyl modified polysiloxane(CPS-1) and CPS-2 as anionic architecture subunits, a series of superpolysiloxanes, QPEPS/CPS-1, QPEPS/CPS-2, and QRS-2/CPS-2, were obtained in the isopropanol media. The applied properties, morphology and chemical compositions of the superpolysiloxanes were systematic investigated by flexibility tester, FESEM, AFM, XPS, and so on. The results indicate the QPEPS/CPS-2 can confer the treated fabrics with good wettability, softness, and antibacterial activity as well as comfortable oily feeling when the ratio of architecture subunit QPEPS to CPS-1 is 1:1. The wettability of the treated fabric is about 4.39 s. And the inhibition rate of the treated fabric rearches 71% against both S. aureus and E. coli.FESEM and AFM results show that supramolecular QPEPS/CPS-1, QPEPS/CPS-2, and QRS-2/CPS-2 all can form macroscopic uniform films on the treated fiber surface. However, there are some small bright hills on the surface of QPEPS/CPS-1 in the AFM images. The Rq of the QPEPS/CPS-1 film reaches 0.857 nm in 2μm×2μm scanning field. Moreover, the surface of QPEPS/CPS-2 film shows a continuous mountains-like morphology. In 2μm×2μm scanning field, the Rq of the QPEPS/CPS-2 film achieves 2.56 nm. Both the above morphologies are estimated to result from the alternate adsorption and aggregate of cationic and anionic architecture subunit. In the QRS-2/CPS-2 AFM images, the morphology is observed that continuous mountain-chains are laced with small hill. The Rq of the QRS-2/CPS-2 film achieves 4.92 nm in 2μm×2μm scanning field. |
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