Fabrication Of Hydrophobic Modified Polysiloxanes And Study On Their Supramolecular System

The wettability of solid surface can be controlled by the change of surface roughness and surface energy.It is important to enhance the hydrophobicity of solid surface by increasing the microroughness and constructing appropriate microcosmic morphology on solid surface.Therefore,a large number of superhydrophobic surfaces have been obtained by designing a variety of micro-nano multi-level composite structure on solid surfaces.However,the influence of the low surface energy chemicals structure on the hydrophobicity solid surfaces is rarely reported.Polysiloxane is one of the common finishing agents with low surface energy and good film-forming capacity.The hybridization of organic polysiloxane and inorganic nanoparticles is a hot topic in the organic-unhybridized materials research.How to graft organic polysiloxane and inorganic nanoparticles effectively and construct a stable multifunctional hydrophobic solid surface are worth further discussion.Therefore,based on the molecular design principle,a series of novel silicone resins with long alkyl or nano-SiO₂ hybrid silicone complexes with long alkyl were firstly designed and synthesized by different chemical reactions.Then the polymers were cured on the cotton fiber or monocrystalline silicon surface.The chemical composition of the surface,and the relationship between the microstructure of the film and the applied properties were studied in depth.Besides,supramoleculars were self-assembled from quaternary ammonium functionalized long alkyl silicone resins and carboxyl modified long alkyl silicone resins or nano-SiO₂ hybrid silicone complexes based on electrostatic interaction in organic solution.Also,the application properties,micro-morphologies,and supramolecular construction mechanism were systematically studied.The main research results are listed as following:?1?A series of novel hydrophobic long alkyl silicone resins PVRST-A and PVRST-B with similar network structure were synthesized by the reactions of long chain/alkoxy co-modified silicone resin,which were prepared from polymethylhydrosiloxane?PHMS?andlongchainalkenesand vinyltriethoxysilane?VTES?via hydrosilylation,with water or hydroxyl silicone oil?PDMS-OH?,respectively.Chemical structures and properties of the synthesized PVRS and PVRST and the emulsions were characterized by nuclear magnetic resonance spectrum?¹H-NMR?,fourier transform infrared spectrum?FT-IR?,transmission electron microscopy?TEM?,particle size analyzer,Zeta potential analyzer,and surface tensiometer.The results indicated that PVRSs were still low surface tension materials and its surface tensions about 24.39²5.78mN/m.When the molar ratio of VTES and LAO?1-hexadecene?was less than 3:7,PVRS and PVRST-A are easily emulsified into a milky white bluish emulsion with a mean size of about 145²05 nm.And the emulsion had good compatibility with cationic resins and non-ionic resins or auxiliaries.FESEM and AFM studies showed that the surface of treated cotton fibers by PVRST-B was coated with a relatively uniform and dense hydrophobic film on the macro level,but the film presented a cluster of needle-like peaks on the micro level.The root means square roughness?Rq?of the PVRST-B film reached 0.497 nm in2?m×2?m scanning field.Calculation by AFM software,the average height of the"needle"peak was 1.587 nm.The"needle"peak in the PVRST-B AFM image maybe result from single,double or multiple clustered beams of long alkyl in the silicone resins side chains.The results of the applied research indicated that PVRST-A can confer the treated fabrics with good hydrophobicity,softness,and the original color of cotton fabric was not affected,its overall application performances were the best,when the ratio of molar VTES to LAO was 1:4,and the content of Si-H bond in PHMS was 0.3%.When the molar ratio of VTES to LAO was 3.5 to 6.5,the WCA of treated fabrics by PVRST-B was 138.0°,and its resilience was the best.In addition,through the study of the relationship between the crosslinking density??e?and film surface hydrophobicity of PVRST,it could easily found that when PVRST formed film on glass surface or fabric surface,the relationship between the crosslinking density and the WCA of PVRST film surface was linear and positive under the crosslinking density ranged from 0.1 to0.42 mol/L.The results showed that with the increase of the crosslinking density of hydrophobic materials,the hydrophobic network structure became denser,which prevented or isolated the contact between hydrophilic particles that were caused by surface chemical inhomogeneity and water.Thus,the hydrophobicity of the material surface was improved.?2?A novel crosslinking network structure hexadecyl/phenyl silicone resin was synthesized by the reactions of hydrosilylation,with phenyl hydrogen silicon resin?HPHSR?,1-hexadecene?HDE?and vinyl silicone?VISIR?.And novel dodecylphenylsiloxane oligomer resin/nanocomposite?PHDESR-SiO₂?was also prepared by grafting copolymerization between dodecyl modified phenylsiloxane resin with pendent epoxy groups?PHDESR?,which were prepared from HPHSR,1-dodecene?DDE?and allyl glycidyl ether?AGE?via hydrosilylation,and amino-functionalized silica nanoparticles?BTEPA-SiO₂?.Chemical structures,chemical compositions,wettability,surface morphology,and thermal properties were investigated by FT-IR,¹H-NMR,X-ray photoelectron spectroscopy?XPS?,SEM,AFM and thermo-gravimetric analysis?TGA?,respectively.The results showed that the film of HPVISR and PHDESR-SiO₂ gave the cotton fabric good hydrophobic properties,the WCA reached 138.5°and 152.5°respectively,and also offered a comfortable flexibility and resilience,compared with PHDESR-SiO₂,HPVISR has better washing resistance.FESEM and AFM studies showed that the microscopic fine morphologies of HPVISR film and PHDESR-SiO₂ film presented multi-scale rough structure with non-uniform morphology.The Rq of the PHDESR-SiO₂ film reached 1.99 nm in 2?m×2?m scanning field,which was greater than the Rq 0.530 nm of HPVISR film.It was confirmed that the PHDESR-SiO₂ film was a trinity superhydrophobic system,which were constructed by nano-SiO₂ particles as the"core",crosslinked silicone resin as the"middle layer network",and clusters of long alkyl groups as the"external molecular brush".Based on the research results of PHDESR-SiO₂ superhydrophobic system,the cross-linking density??e?was introduced into Cassie theoretical model to established the relationship among the cross-linking density,surface roughness structure and static contact angle of water.The superhydrophobic mechanism of the HPVISR film and PHDESR-SiO₂ hybrid film on the cotton fibers surface had been analyzed by the modified Cassie's mode and the crosslinking density of the films was 0.37 mol/L,as well as the area portions of the liquid/vapor contact area was 84%on the composite interface of the PHDESR-SiO₂ treated fabric surface.And the existence of the hydrophobic material with dense crosslinked network structure and air in the rugged concave and convex structure could effectively isolates the water droplets from penetrating into the fiber,which was conducive to the improvement of the hydrophobic property of the film surface.?3?Long chain quaternary ammonium polysiloxane?RQS-1?and long carbon chain quaternary ammonium silicon resin?RQS-2?were synthesized by the reaction of epoxy group polysiloxane or epoxy group silicon resin,which were prepared from PHMS or long carbon chain alkyl waxy hydrosilicone?HDRQ?and AGE via hydrosilylation,with di-methyl-dodecyl amine?DMDA?,respectively.A carboxyl modified silicon resin?CRS-1?was prepared by the reaction of N-?-?aminoethyl?-?-amopropyl trimethoxysilane?KH-791?with maleic anhydride?MAn?via ring-opening hydrolysis condensation.A carboxyl long-chain alkyl/phenyl silicone resin/nanocomposite?CRS-2/SiO₂?and a waxy carboxyl long-chain alkyl silicone resin/nanocomposite?CRS-3/SiO₂?were prepared by grafting reaction with carboxyl long-chain alkyl/phenyl silicone resin?CRS-2?or waxy carboxyl long-chain alkyl silicone resin?CRS-3?,which were prepared from PHDESR or long carbon chain alkyl epoxy waxy silicone?DDRQ?and KH-791as well as MAn via ring-opening hydrolysis condensation,and nano-silica,respectively.Chemical structures were investigated by FT-IR,¹H-NMR.XRD analysis confirmed that the nano-SiO₂ in the composites were amorphous.Then,RQS-1 and RQS-2 were used as cationic building subunits,CRS-1,CRS-2,CRS-3,CRS-2-SiO₂ and CRS-3-SiO₂ were used as anionic building subunits.Five new supramoleculars A?RQS-1/CRS-1?,B?RQS-2/CRS-2?,C?RQS-1/CRS-3?,D?RQS-1/CRS-2-SiO₂?and E?CRC-SiO₂?were constructed by electrostatic self-assembly or layer upon layer self-assembly method.The supramolecular aggregates with multi-unit structure and the best comprehensive application performance were formed by adsorbed alternately between anionic and cation,when the ratio of building subunit of A RQS-1 to CRS-1 was 1:1,B RQS-2 to CRS-2 was 1:1,C RQS-1 to CRS-3 was 2:3,and D RQS-1 to CRS-2-SiO₂was 1:1,respectively.The water contact angle of the supramolecular E?CRC-SiO₂?,which was constructed by layer upon layer self-assembly,was increased to155.5°.The results of FESEM and AFM showed that all the five supramolecules had good film-forming property.The microscopic morphologies of supramolecular A?RQS-1/CRS-1?film presented clusters of bright peak packets with irregular shapes,different lengths and thickness,and the Rq of the A?RQS-1/CRS-1?film reached 2.500nm in 2?m×2?m scanning field.The microscopic morphologies of supramolecular B?RQS-2/CRS-2?film presented dome-like assembly of varying sizes,with the maximum size of the assembly was up to 0.5?m,and multiscale micro-nano structures were formed from dome-like assembly,small micro-assemblies and construction of primitive aggregates.The Rq of the B?RQS-2/CRS-2?film reached 3.250 nm in 2?m×2?m scanning field.The film of supramolecular C?RQS-1/CRS-3?was a relatively uniform stone forest-like peaks cluster,which was similar to the film morphology of supramolecular A?RQS-1/CRS-1?,and its film Rq reached 4.588 nm.The film of D?RQS-1/CRS-2-SiO₂?presented particle size ranging from tens of nanometers to hundreds of nanometers,with irregular shape and uneven hilly morphology,and the largest particle size of the assembly could reach 2?m.In the scanning range of 2?m×2?m,clusters of forest needle-like peaks appeared on the uneven dome-like peaks,and the Rq of the D?RQS-1/CRS-2-SiO₂?film was 3.36 nm.Supramolecular E?CRC-SiO₂?presented clusters of agglomerated nanoparticles,and three-dimensional and phase diagrams showed uneven and round stone forest-like peaks.The Rq of the E?CRC-SiO₂?film was as high as 17.66 nm,which was composed of supramolecular assemblies with particle sizes ranging from dozens to hundreds,in2?m×2?m scanning field.Ultimately,the self-assembly mechanisms of the supramolecular A,B,C,D,and E were studied,the results showed that the cationic and anionic building subunits existed in the form of nanoparticles structure,resin reticular structure,linear group structure with stretching and curling,as well as molecular brush etc.,which were exist in several or many forms,in polar mixed medium of isopropyl alcohol and ethyl acetate.The cationic building subunits and anionic building subunits of A(RQS-1/CRS-1,B?RQS-2/CRS-2?or C?RQS-1/CRS-3?,electrostatic self-assembly occurred under the action of electrostatic force,and the supramolecular aggregation with multi-unit structures were formed by alternating adsorption.The larger the degree of alternating adsorption,the larger the three-dimensional scale of supramolecular assembly.The supramolecular D?RQS-1/CRS-2-SiO₂?was constructed by nano-SiO₂ particles as the"core",crosslinked silicone resin as the"middle layer network",and clusters of long alkyl groups as the"external molecular brush".Supramolecular E?CRC-SiO₂?was a multilayer supramolecular composite assembly formed by self-assembly of layers under the action of electrostatic force.