Elastomers are widely used in various fields owing to their excellent tensile properties.Recyclable and self-healing properties are key to extending the service life of elastomers.Accumulating evidence indicates that ...Elastomers are widely used in various fields owing to their excellent tensile properties.Recyclable and self-healing properties are key to extending the service life of elastomers.Accumulating evidence indicates that dynamic covalent chemistry has emerged as a powerful tool for constructing recyclable and self-healing materials.In this work,we demonstrate the preparation of a recyclable and self-healable polydimethylsiloxane(PDMS)elastomer based on the Knoevenagel condensation(KC)reaction.This PDMS elastomer was prepared by the KC reaction catalyzed by 4-dimethylaminopyridine(DMAP).The obtained PDMS elastomer exhibited an elongation at break of 266%,a tensile strength of 0.57 MPa,and a good thermal stability(Td=357℃).In addition,because of the presence of dynamic C=C bonds formed by the KC reaction and low glass transition temperature(Tg=-117℃).This PDMS exhibited good self-healing and recycling properties at room temperature and could be reprocessed by hot pressing.In addition,the PDMS elastomer exhibits good application prospects in the fields of adhesives and flexible electronic devices.展开更多
The formation of segregated structure has been demonstrated as an effective strategy for achieving ex-ceptional electromagnetic interference(EMI)shielding performance at low filler loadings.However,the acquisition of ...The formation of segregated structure has been demonstrated as an effective strategy for achieving ex-ceptional electromagnetic interference(EMI)shielding performance at low filler loadings.However,the acquisition of polymer particles and the formation of interactions with conductive fillers remain signifi-cant challenges for polydimethylsiloxane,which are crucial to the construction of a segregated structure.In this work,MXene sheets were functionalized and assembled onto the surface of polydimethylsilox-ane microspheres via hydrophobic interaction.Subsequently,functionalized MXene/polydimethylsiloxane(FMP)composites with a segregated structure were fabricated by filtration and hot-pressing.The FMP composite containing 8.22 wt.%MXene exhibited a high electrical conductivity of 99.4 S m^(−1)and a sat-isfactory EMI shielding effectiveness/thickness(EMI SE/d)of 31.3 dB mm^(−1).Furthermore,the FMP com-posite demonstrated excellent reliability with over 90%retention of EMI shielding effectiveness under harsh environments such as ultra-high/low temperatures and acidic/alkaline solutions.Additionally,the photothermal conversion performance of FMP composites and the capacitive sensing performance of the sensor based on FMP composites indicated their potential for managing body temperature and moni-toring human movement.Consequently,FMP composites show great promise in wearable electronics for effective electromagnetic interference shielding,thermal management and capacitive sensing.展开更多
Microneedles(MNs)have attracted increasing attention as a transdermal delivery system(TDDS)[1].However,traditional volatile Chinese medicines cannot be dissolved in conventional soluble MN materials,such as hyaluronic...Microneedles(MNs)have attracted increasing attention as a transdermal delivery system(TDDS)[1].However,traditional volatile Chinese medicines cannot be dissolved in conventional soluble MN materials,such as hyaluronic acid and chitosan,making it difficult for many traditional Chinese medicine ingredients to be applied to MN.Elemene(ELE)was successfully isolated from Curcuma longa,and has numerous antitumor and curative effects[2].展开更多
Polydimethylsiloxane(PDMS)is considered a low surface energy material widely used in(super)hydrophobic modification.In this paper,the high hydrophobic melamine sponges(MS)were modified with commercial aminopropyl func...Polydimethylsiloxane(PDMS)is considered a low surface energy material widely used in(super)hydrophobic modification.In this paper,the high hydrophobic melamine sponges(MS)were modified with commercial aminopropyl functionalized polydimethylsiloxane(NH_(2)-PDMS)with different molecular mass.The chemical composition,surface morphology,and wettability of the NH_(2)-PDMS-modified MS were investigated by X-ray photoelectron spectroscopy(XPS),attenuated total reflection Fourier transform infrared spectroscopy(ATR-FTIR)and contact angle test.Owing to the porous structure and high hydrophobicity,NH_(2)-PDMS-modified MS possesses remarkable absorption capacity(ranging from 46 to 155 times their own mass).Simultaneously,it can effectively separate oil-water mixtures with high separation efficiencies exceeding 98.2%.NH_(2)-PDMS-modified MS has no obvious change after 10 cycles of oil-water separation.The results demonstrate PDMS molecular mass on surface can revise material properties and achieve high separation efficiencies in oil-water separation.展开更多
Development of polymers with underwater self-healing and antifouling properties is crucial,particularly in harsh marine environments.In this study,polydimethylsiloxane(PDMS)-based antifouling polymers with tunable sel...Development of polymers with underwater self-healing and antifouling properties is crucial,particularly in harsh marine environments.In this study,polydimethylsiloxane(PDMS)-based antifouling polymers with tunable self-healing capabilities in aqueous conditions were fabricated by incorporating amphiphilic segments and Fe^(3+)-catechol dynamic coordination crosslinking.The microphase formed within the PDMS matrix imparted static antifouling properties to the coatings.The mechanical properties of the damaged sample were restored at room temperature in an aqueous environment for 24 h,achieving a self-healing efficiency of almost 100%.The synthesized material exploited the dynamic coordination between Fe^(3+) and catechol to facilitate underwater self-healing.No bacterial adhesion was observed at the scratch site after the coating was repaired.This material enables the long-term antifouling and autonomous repair of marine vessels and sensors,thereby reducing maintenance costs.展开更多
A reliable,high-performance coating procedure was developed using PDMS to modify a duplex MAO/DLC coating on an AZ31B Mg alloy.First,the duplex MAO/DLC coating was fabricated via a combined MAO and unbalanced magnetro...A reliable,high-performance coating procedure was developed using PDMS to modify a duplex MAO/DLC coating on an AZ31B Mg alloy.First,the duplex MAO/DLC coating was fabricated via a combined MAO and unbalanced magnetron sputter process.Subsequently,a PDMS solution was used to modify the MAO/DLC coating via a conventional dip-coating method.The surface characteristics,bond strength,hardness,tribological behaviour,and corrosion resistance of the coated samples were evaluated via SEM,CA,Raman spectroscopy,friction and wear behaviour,polarisation curve,and NSS tests.The PDMS modification reduced the HIT of MAO/DLC coating from 15.96 to 8.34GPa;this is ascribed to the penetration of PDMS,which has good rheological properties to form a viscoelastic Si-based organic polymer layer on the MAO/DLC coating.However,the PDMS-modified MAO/DLC coating was denser,hydrophobic,and had higher bond strength compared with MAO-and MAO/DLC-coated samples.Moreover,the PDMS modification reduced the COF and wear rate of the duplex MAO/DLC coating.This indicates that the PDMS improved the tribological behaviour owing to the transferred Si oxide that originated from the Si-O network of the PDMS,as well as the low graphitisation of the DLC layer during sliding.Furthermore,the corrosion current density of the MAO/DLC-coated sample modified by PDMS for 10min decreased by two order of magnitude compared with that of the MAO/DLC-coated sample but by five orders of magnitude compared with that of the bare substrate.The NSS tests proved that the PDMS layer slowed the corrosion of the Mg alloy under long-term service,enhancing the corrosion protection efficiency.The results are attributed to the high bond strength and lubricant MAO/DLC layer,and the dual role of sealing and hydrophobicity of PDMS.Therefore,PDMS modification is promising for the fabrication of protective materials for Mg alloys that require corrosion and wear resistance.展开更多
Worldwide environment has resulted in a limit on the sulfur content of gasoline.It is urgent to investigate the desulfurization of gasoline.The polydimethylsiloxane(PDMS)/polyetherimide(PEI)composite membranes were pr...Worldwide environment has resulted in a limit on the sulfur content of gasoline.It is urgent to investigate the desulfurization of gasoline.The polydimethylsiloxane(PDMS)/polyetherimide(PEI)composite membranes were prepared by casting a PDMS solution onto porous PEI substrates and characterized by scanning electron microscope(SEM).The membranes were used for sulfur removal from gasoline by pervaporation.The effects of feed temperature,sulfur content in the feed and PDMS layer thickness on membrane performance were investigated,and an activation energy of permeation was obtained.Experimental results indicated that higher feed temperature yielded higher total flux and lower sulfur enrichment factor.The total flux varied little with the increase of sulfur content in the feed,but the sulfur enrichment factor first increased with the amount of thiophene added into the gasoline,and then the variation was little.The increase of PDMS layer thickness resulted in a smaller flux but a larger sulfur enrichment factor.The result indicates that the PDMS/PEI composite membranes are promising for desulfurization by pervaporation.展开更多
Titanium complex greases were prepared by using naphthenic mineral oil and polydimethylsiloxane as the mixed base oil. The effect of polydimethylsiloxane molecular weight and polydimethylsiloxane content in mixed base...Titanium complex greases were prepared by using naphthenic mineral oil and polydimethylsiloxane as the mixed base oil. The effect of polydimethylsiloxane molecular weight and polydimethylsiloxane content in mixed base oil on the physicochemical and tribological properties of titanium complex greases was investigated.As compared to the sole mineral oil-based titanium complex grease, the use of polydimethylsiloxane(H201-350)as a co-base oil increased the dropping point from 310 to 329℃, decreased the oil separation from 3.7% to 2.3%,reduced the corrosion extent, and obviously improved the tribological properties. When the mixed oil-based titanium complex grease was used as a lubricant, lubricating films of polydimethylsiloxane were probably formed on the surfaces of friction pairs, giving good lubricating property.展开更多
Large-area polydimethylsiloxane(PDMS)films with variably sized moth-eye structures were fabricated to improve the efficiency of perovskite solar cells.An approach that incorporated photolithography,bilayer PDMS deposi...Large-area polydimethylsiloxane(PDMS)films with variably sized moth-eye structures were fabricated to improve the efficiency of perovskite solar cells.An approach that incorporated photolithography,bilayer PDMS deposition and replication was used in the fabrication process.By simply attaching the moth-eye PDMS films to the transparent substrates of perovskite solar cells,the optical properties of the devices could be tuned by changing the size of the moth-eye structures.The device with 300-nm moth-eye PDMS films greatly enhanced power conversion efficiency of ~21 % due to the antireflective effect of the moth-eye structure.Furthermore,beautiful coloration was observed on the 1000-nm moth-eye PDMS films through optical interference caused by the diffraction grating effect.Our results imply that moth-eye PDMS films can greatly enhance the efficiency of perovskite solar cells and building-integrated photovoltaics.展开更多
Constructing controllable thermal conduction networks is the key to efficiently improve thermal conductivities of polymer composites.In this work,graphite oxide(GO)and functionalized carbon nanotubes(f-CNTs)are combin...Constructing controllable thermal conduction networks is the key to efficiently improve thermal conductivities of polymer composites.In this work,graphite oxide(GO)and functionalized carbon nanotubes(f-CNTs)are combined to prepare“Line-Plane”-like hetero-structured thermally conductive GO@f-CNTs fillers,which are then performed to construct controllable 3D GO@f-CNTs thermal conduction networks via selfsacrificing template method based on oxalic acid.Subsequently,thermally conductive GO@f-CNTs/polydimethylsiloxane(PDMS)composites are fabricated via casting method.When the size of oxalic acid is 0.24 mm and the volume fraction of GO@f-CNTs is 60 vol%,GO@f-CNTs/PDMS composites present the optimal thermal conductivity coefficient(λ,4.00 W·m^(-1)·K^(-1)),about 20 times that of theλof neat PDMS(0.20 W·m^(-1)·K^(-1)),also much higher than theλ(2.44 W·m^(-1)·K^(-1))of GO/f-CNTs/PDMS composites with the same amount of randomly dispersed fillers.Meanwhile,the obtained GO@f-CNTs/PDMS composites have excellent thermal stability,whoseλdeviation is only about 3%after 500 thermal cycles(20-200℃).展开更多
The intensive development of micro-/nanotechnologies offers a new route to construct sophisticated architectures of emerging soft electronics.Among the many classes of stretchable materials,micro-/nanostructured poly(...The intensive development of micro-/nanotechnologies offers a new route to construct sophisticated architectures of emerging soft electronics.Among the many classes of stretchable materials,micro-/nanostructured poly(dimethylsiloxane)(PDMS)has emerged as a vital building block based on its merits of flexibility,stretchability,simple processing,and,more importantly,high degrees of freedom of incorporation with other functional materials,including metals and semiconductors.The artificially designed geometries play important roles in achieving the desired mechanical and electrical performances of devices and thus show great potential for applications in the fields of stretchable displays,sensors and actuators as well as in health-monitoring device platforms.Meanwhile,novel lithographic methods to produce stretchable platforms with superb reliability have recently attracted research interest.The aim of this review is to comprehensively summarize the progress regarding micro-/nanostructured PDMS and their promising soft electronic applications.This review is concluded with a brief outlook and further research directions.展开更多
The pervaporation behavior of fermentation broth was investigated experimentally and compared with those started with ethanol mixtures. Ethanol was produced by Saccharomyces cerevisiae utilizing technical grade glucos...The pervaporation behavior of fermentation broth was investigated experimentally and compared with those started with ethanol mixtures. Ethanol was produced by Saccharomyces cerevisiae utilizing technical grade glucose and recovered by pervaporation using a composite polydimethylsiloxane (PDMS) membrane prepared in our laboratory. Ethanol concentration in fermentation broth decreased to a relatively low level when pervaporation was coupled with fermentation. The more active cells appeared in the fermentation broth, the better the membrane performance was.展开更多
Polydimethylsiloxane (PDMS) rubber latex with two sorts of sensitizers, trimethylol propane tri-methacrylate (TMPTMA) and diethylene glycol di-acrylate (DEGDA), was irradiated with γ-rays and electron beams in variou...Polydimethylsiloxane (PDMS) rubber latex with two sorts of sensitizers, trimethylol propane tri-methacrylate (TMPTMA) and diethylene glycol di-acrylate (DEGDA), was irradiated with γ-rays and electron beams in various conditions. The radiation crosslinking reaction of PDMS occurs in the inner phase of the latex and is relatively isolated from the water phase. Therefore the oxygen and the radicals produced by the radiolysis reaction of water almost have no effect on the crosslinking reaction of polymer. The experimental data correspond with the Charlesby-Pinner relationship in the main. The gelation doses, degree of crosslinking and degradation as well as G values of crosslinking were calculated. From them, the sensitization coefficients were derived to offer a quantitative measurement of the enhancing effect of sensitizer on the radiation crosslinking.展开更多
The fabrication of a separation layer on the inner surface of a hollow fiber (HF) substrate to form an HF composite membrane offers exciting opportunities for industrial applications, although challenges remain. This ...The fabrication of a separation layer on the inner surface of a hollow fiber (HF) substrate to form an HF composite membrane offers exciting opportunities for industrial applications, although challenges remain. This work reports on the fabrication of a polydimethylsiloxane (PDMS) composite membrane on the inner surface of a single-channel or multi-channel ceramic HF via a proposed coating/crossflow approach. The nanostructures and transport properties of the PDMS HF composite membranes were optimized by controlling the polymer concentration and coating time. The morphology, surface chemistry, interfacial adhesion, and separation performance of the membranes were characterized by fieldemission scanning electron microscope (FE-SEM), attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy, the nano-indentation/scratch technique, and pervaporation (PV) recovery of bio-butanol, respectively. The formation mechanism for the deposition of the PDMS layer onto the inner surface of the ceramic HF was studied in detail. The optimized inner surface of the PDMS/ceramic HF composite membranes with a thin and defect-free separation layer exhibited a high flux of ~1800 gm-2h-1 and an excellent separation factor of 35–38 for 1 wt% n-butanol/water mixtures at 60 C. The facile coating/cross-flow methodology proposed here shows great potential for fabricating inner-surface polymer-coated HFs that have broad applications including membranes, adsorbents, composite materials, and more.展开更多
A modified solution-diffusion model was established based on Flory-Huggins thermodynamic theory and Fujita's free volume theory. This model was used for description of the mass transfer of removal benzene from dil...A modified solution-diffusion model was established based on Flory-Huggins thermodynamic theory and Fujita's free volume theory. This model was used for description of the mass transfer of removal benzene from dilute aqueous solutions through polydimethylsiloxane (PDMS) membranes. The effect of component concentration on the interaction parameter between components, that of the polymer membrane on the selectivity to benzene, and that of feed concentration and temperature on the permeation flux and separation factor of benzene/water through PDMS membranes were investigated. Calculated pervaporation fluxes of benzene and water were compared with the experimental results and were in good agreement with the experimental data.展开更多
Pervaporation(PV)is an emerging separation technique for liquid mixture.Mixed matrix membranes(MMMs)often demonstrate trade-off relationship between separation factor and flux.In this study,by changing the organic lin...Pervaporation(PV)is an emerging separation technique for liquid mixture.Mixed matrix membranes(MMMs)often demonstrate trade-off relationship between separation factor and flux.In this study,by changing the organic linkers(2-methyl imidazolate,imidazole-2-carboxaldehyde,2-ethyl imidazolate),ZIF-8,ZIF-90 and MAF-6 were prepared and filled in polydimethylsiloxane(PDMS)membranes for dealcoholization of 5%(mass)n-butanol solution,and the membranes properties and pervaporation performances were adjusted.Compared with the pure PDMS membrane,the addition of ZIF-8 resulted in a 9%increase in flux(1136 g·m^(-2)·h^(-1))and a 22.5%increase in separation factor(28.3),displaying antitrade-off effect.For the MAF-6/PDMS MMMs(2.0%mass loading),the pervaporation separation index(PSI)and separation factor were 32347 g·m^(-2)·h^(-1) and 58.6 respectively(increased by 34%and 154%in contrast with that of the pure PDMS membrane),and the corresponding permeation flux was 552 g·m^(-2)·h^(-1),presenting great potential in the removal butanol from water.It was deduced that the large aperture size combined with moderate hydrophobicity of metal–organic frameworks(MOFs)favor the concurrent increase in permeability and selectivity.展开更多
The surface of calcium carbonate(CaCO_3)particles was modified with stearic acid(SA)and the chemical structures of the product were characterized by FT-IR analysis.The interaction between polydimethylsiloxane(PDMS)and...The surface of calcium carbonate(CaCO_3)particles was modified with stearic acid(SA)and the chemical structures of the product were characterized by FT-IR analysis.The interaction between polydimethylsiloxane(PDMS)and CaCO_3 fillers with different surface character was investigated by means of dynamic rheological and bound rubber tests for uncured compounds and mechanical properties measurements for the corresponding vulcanites.The results of dynamic tests indicate that with the increase of SA mass fraction...展开更多
A novel hydroxypolyether blocked polydimethylsiloxane, poly（ethylene oxide） propyl-b-polydimethylsiloxane-b-propyl poly（ethylene oxide） （PEO-b-PDMS-b-PEO） was synthesized by simple hydrosilation reaction of poly...A novel hydroxypolyether blocked polydimethylsiloxane, poly（ethylene oxide） propyl-b-polydimethylsiloxane-b-propyl poly（ethylene oxide） （PEO-b-PDMS-b-PEO） was synthesized by simple hydrosilation reaction of poly（ethylene glycol） monoallyl ether with α,ω-dihydrogen terminated PDMS （HPDMS）. Fourier transform infrared spectroscopy （FTIR） and IH NMR were used to identify the structure of PEO-b-PDMS-b-PEO and intermediate product HPDMS. Based on the effect investigations of temperature, reactant molar ratio, catalyst and time on the hydrosilation, it was found that the conversion of Si-H bond to SiC bond increased with the increase of catalyst and time, and the reaction completed when the content of catalyst was 22μg/g and the time was 5 h, respectively. Urethane reaction of OH and NCO group confirms that PEO-b-PDMS-b-PEO is more reactive toward to diisocyanate than α,ω-dihydroxylbutyl terminated PDMS.展开更多
Block copolymers with different backbone compositions have been prepared by the condensation of dimethylamino terminated poly（dimethylsiloxane） （PDMS） and hydroquinone terminated poly（phthalazinone ether nitrile...Block copolymers with different backbone compositions have been prepared by the condensation of dimethylamino terminated poly（dimethylsiloxane） （PDMS） and hydroquinone terminated poly（phthalazinone ether nitrile） （PPEN） in the presence of chlorobenzcne/N-methyl pyrrolidone （NMP） as solvents. The products were characterized by FTIR, ^1H NMR and gel permeation chromatography. Differential scanning calorimetry analysis indicated that the block copolymers showed separated microphase.展开更多
Hydrosilylation has been carried out between Si-H terminated polydimethylsiloxanes with narrow molecular weight distribution and protected 3-allyloxy-l,2-propanediol, and after subsequently alcoholyzed, α-{3-[（2,3-d...Hydrosilylation has been carried out between Si-H terminated polydimethylsiloxanes with narrow molecular weight distribution and protected 3-allyloxy-l,2-propanediol, and after subsequently alcoholyzed, α-{3-[（2,3-dihydroxy）propoxy]propyl}-ω- butyl-polydimethylsiloxanes with varying number of （（Si（CH3）2-O） unit were obtained. At each step, the produced compounds were carefully characterized. The results showed that each step was successfully carried out and target products were achieved.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51973025 and 52222307)Jilin Science and Technology Bureau(Nos.20220204107YY and 20230204086YY)+1 种基金Changchun Science and Technology Bureau(No.21ZGY06)Jilin Province Development and Reform Commission(No.2023C028-4).
文摘Elastomers are widely used in various fields owing to their excellent tensile properties.Recyclable and self-healing properties are key to extending the service life of elastomers.Accumulating evidence indicates that dynamic covalent chemistry has emerged as a powerful tool for constructing recyclable and self-healing materials.In this work,we demonstrate the preparation of a recyclable and self-healable polydimethylsiloxane(PDMS)elastomer based on the Knoevenagel condensation(KC)reaction.This PDMS elastomer was prepared by the KC reaction catalyzed by 4-dimethylaminopyridine(DMAP).The obtained PDMS elastomer exhibited an elongation at break of 266%,a tensile strength of 0.57 MPa,and a good thermal stability(Td=357℃).In addition,because of the presence of dynamic C=C bonds formed by the KC reaction and low glass transition temperature(Tg=-117℃).This PDMS exhibited good self-healing and recycling properties at room temperature and could be reprocessed by hot pressing.In addition,the PDMS elastomer exhibits good application prospects in the fields of adhesives and flexible electronic devices.
基金supported by the Fundamental Research Funds for the Central Universities(No.D5000220252)the funds for Ministry of Industry and Information Technology(No.MJZ44N22)Shaanxi Undergraduate Training Program for Innovation and Entrepreneurship(No.S202310699509).
文摘The formation of segregated structure has been demonstrated as an effective strategy for achieving ex-ceptional electromagnetic interference(EMI)shielding performance at low filler loadings.However,the acquisition of polymer particles and the formation of interactions with conductive fillers remain signifi-cant challenges for polydimethylsiloxane,which are crucial to the construction of a segregated structure.In this work,MXene sheets were functionalized and assembled onto the surface of polydimethylsilox-ane microspheres via hydrophobic interaction.Subsequently,functionalized MXene/polydimethylsiloxane(FMP)composites with a segregated structure were fabricated by filtration and hot-pressing.The FMP composite containing 8.22 wt.%MXene exhibited a high electrical conductivity of 99.4 S m^(−1)and a sat-isfactory EMI shielding effectiveness/thickness(EMI SE/d)of 31.3 dB mm^(−1).Furthermore,the FMP com-posite demonstrated excellent reliability with over 90%retention of EMI shielding effectiveness under harsh environments such as ultra-high/low temperatures and acidic/alkaline solutions.Additionally,the photothermal conversion performance of FMP composites and the capacitive sensing performance of the sensor based on FMP composites indicated their potential for managing body temperature and moni-toring human movement.Consequently,FMP composites show great promise in wearable electronics for effective electromagnetic interference shielding,thermal management and capacitive sensing.
基金supported by Shandong Provincial Natural Science Foundation Innovation and Development Joint Project,China(Grant No.:ZR2021LZY039)Zhejiang Provincial Traditional Chinese Medicine Science and Technology Plan,China(Grant No.:2021ZB184)。
文摘Microneedles(MNs)have attracted increasing attention as a transdermal delivery system(TDDS)[1].However,traditional volatile Chinese medicines cannot be dissolved in conventional soluble MN materials,such as hyaluronic acid and chitosan,making it difficult for many traditional Chinese medicine ingredients to be applied to MN.Elemene(ELE)was successfully isolated from Curcuma longa,and has numerous antitumor and curative effects[2].
基金Project(2025JJ70532)supported by the Natural Science Foundation of Hunan Province,ChinaProjects(21862009,21563016)supported by the National Natural Science Foundation of ChinaProject(2022GX020)supported by the Taian Science and Technology Innovation Development Project,China。
文摘Polydimethylsiloxane(PDMS)is considered a low surface energy material widely used in(super)hydrophobic modification.In this paper,the high hydrophobic melamine sponges(MS)were modified with commercial aminopropyl functionalized polydimethylsiloxane(NH_(2)-PDMS)with different molecular mass.The chemical composition,surface morphology,and wettability of the NH_(2)-PDMS-modified MS were investigated by X-ray photoelectron spectroscopy(XPS),attenuated total reflection Fourier transform infrared spectroscopy(ATR-FTIR)and contact angle test.Owing to the porous structure and high hydrophobicity,NH_(2)-PDMS-modified MS possesses remarkable absorption capacity(ranging from 46 to 155 times their own mass).Simultaneously,it can effectively separate oil-water mixtures with high separation efficiencies exceeding 98.2%.NH_(2)-PDMS-modified MS has no obvious change after 10 cycles of oil-water separation.The results demonstrate PDMS molecular mass on surface can revise material properties and achieve high separation efficiencies in oil-water separation.
基金supported by Beijing Municipal Natural Science Foundation(No.2242053)National Natural Science Foundation of China(No.22275012).
文摘Development of polymers with underwater self-healing and antifouling properties is crucial,particularly in harsh marine environments.In this study,polydimethylsiloxane(PDMS)-based antifouling polymers with tunable self-healing capabilities in aqueous conditions were fabricated by incorporating amphiphilic segments and Fe^(3+)-catechol dynamic coordination crosslinking.The microphase formed within the PDMS matrix imparted static antifouling properties to the coatings.The mechanical properties of the damaged sample were restored at room temperature in an aqueous environment for 24 h,achieving a self-healing efficiency of almost 100%.The synthesized material exploited the dynamic coordination between Fe^(3+) and catechol to facilitate underwater self-healing.No bacterial adhesion was observed at the scratch site after the coating was repaired.This material enables the long-term antifouling and autonomous repair of marine vessels and sensors,thereby reducing maintenance costs.
基金This work was supported by Special Fund for Local Science and Technology Development from the Ministry of Science and Technology of China(2020ZYD053)Science and Technology Planning Project of Zigong(2019YYJC22)Opening Project of Key Laboratories of Fine Chemicals and Surfactants in Sichuan Provincial Universities(2020JXY05).
文摘A reliable,high-performance coating procedure was developed using PDMS to modify a duplex MAO/DLC coating on an AZ31B Mg alloy.First,the duplex MAO/DLC coating was fabricated via a combined MAO and unbalanced magnetron sputter process.Subsequently,a PDMS solution was used to modify the MAO/DLC coating via a conventional dip-coating method.The surface characteristics,bond strength,hardness,tribological behaviour,and corrosion resistance of the coated samples were evaluated via SEM,CA,Raman spectroscopy,friction and wear behaviour,polarisation curve,and NSS tests.The PDMS modification reduced the HIT of MAO/DLC coating from 15.96 to 8.34GPa;this is ascribed to the penetration of PDMS,which has good rheological properties to form a viscoelastic Si-based organic polymer layer on the MAO/DLC coating.However,the PDMS-modified MAO/DLC coating was denser,hydrophobic,and had higher bond strength compared with MAO-and MAO/DLC-coated samples.Moreover,the PDMS modification reduced the COF and wear rate of the duplex MAO/DLC coating.This indicates that the PDMS improved the tribological behaviour owing to the transferred Si oxide that originated from the Si-O network of the PDMS,as well as the low graphitisation of the DLC layer during sliding.Furthermore,the corrosion current density of the MAO/DLC-coated sample modified by PDMS for 10min decreased by two order of magnitude compared with that of the MAO/DLC-coated sample but by five orders of magnitude compared with that of the bare substrate.The NSS tests proved that the PDMS layer slowed the corrosion of the Mg alloy under long-term service,enhancing the corrosion protection efficiency.The results are attributed to the high bond strength and lubricant MAO/DLC layer,and the dual role of sealing and hydrophobicity of PDMS.Therefore,PDMS modification is promising for the fabrication of protective materials for Mg alloys that require corrosion and wear resistance.
基金Supported by the National Basic Research Program of China(2009CB623404)the National Natural Science Foundation of China(50708109,20736003)the National High Technology Research and Development Program of China(2007AA06Z317)
文摘Worldwide environment has resulted in a limit on the sulfur content of gasoline.It is urgent to investigate the desulfurization of gasoline.The polydimethylsiloxane(PDMS)/polyetherimide(PEI)composite membranes were prepared by casting a PDMS solution onto porous PEI substrates and characterized by scanning electron microscope(SEM).The membranes were used for sulfur removal from gasoline by pervaporation.The effects of feed temperature,sulfur content in the feed and PDMS layer thickness on membrane performance were investigated,and an activation energy of permeation was obtained.Experimental results indicated that higher feed temperature yielded higher total flux and lower sulfur enrichment factor.The total flux varied little with the increase of sulfur content in the feed,but the sulfur enrichment factor first increased with the amount of thiophene added into the gasoline,and then the variation was little.The increase of PDMS layer thickness resulted in a smaller flux but a larger sulfur enrichment factor.The result indicates that the PDMS/PEI composite membranes are promising for desulfurization by pervaporation.
基金Supported by the National Natural Science Foundation of China(21506078,21506082)China Postdoctoral Science Foundation(2016M591786,2016M601739)
文摘Titanium complex greases were prepared by using naphthenic mineral oil and polydimethylsiloxane as the mixed base oil. The effect of polydimethylsiloxane molecular weight and polydimethylsiloxane content in mixed base oil on the physicochemical and tribological properties of titanium complex greases was investigated.As compared to the sole mineral oil-based titanium complex grease, the use of polydimethylsiloxane(H201-350)as a co-base oil increased the dropping point from 310 to 329℃, decreased the oil separation from 3.7% to 2.3%,reduced the corrosion extent, and obviously improved the tribological properties. When the mixed oil-based titanium complex grease was used as a lubricant, lubricating films of polydimethylsiloxane were probably formed on the surfaces of friction pairs, giving good lubricating property.
基金supported in part by the Global Frontier R&D Program of the Center for Multiscale Energy Systems funded by the National Research Foundation under the Ministry of Education, Science and Technology, Korea (2012M3A6A7054855)supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) (No. 2017RICIB1005834)newly appointed professor research fund of Hanbat National University in 2018
文摘Large-area polydimethylsiloxane(PDMS)films with variably sized moth-eye structures were fabricated to improve the efficiency of perovskite solar cells.An approach that incorporated photolithography,bilayer PDMS deposition and replication was used in the fabrication process.By simply attaching the moth-eye PDMS films to the transparent substrates of perovskite solar cells,the optical properties of the devices could be tuned by changing the size of the moth-eye structures.The device with 300-nm moth-eye PDMS films greatly enhanced power conversion efficiency of ~21 % due to the antireflective effect of the moth-eye structure.Furthermore,beautiful coloration was observed on the 1000-nm moth-eye PDMS films through optical interference caused by the diffraction grating effect.Our results imply that moth-eye PDMS films can greatly enhance the efficiency of perovskite solar cells and building-integrated photovoltaics.
基金financially supported by the National Natural Science Foundation of China(No.51973173)Technological Base Scientific Research Projects(Highly Thermally Conductive Nonmetal Materials)+3 种基金Natural Science Foundation of Chongqing,China(No.2023NSCQ-MSX2547)Shaanxi Province Key Research and Development Plan Project(No.2023-YBGY-461)Fundamental Research Funds for the Central Universities,the Innovation Capability Support Program of Shaanxi(No.2024RS-CXTD-57)financially supported by Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars。
文摘Constructing controllable thermal conduction networks is the key to efficiently improve thermal conductivities of polymer composites.In this work,graphite oxide(GO)and functionalized carbon nanotubes(f-CNTs)are combined to prepare“Line-Plane”-like hetero-structured thermally conductive GO@f-CNTs fillers,which are then performed to construct controllable 3D GO@f-CNTs thermal conduction networks via selfsacrificing template method based on oxalic acid.Subsequently,thermally conductive GO@f-CNTs/polydimethylsiloxane(PDMS)composites are fabricated via casting method.When the size of oxalic acid is 0.24 mm and the volume fraction of GO@f-CNTs is 60 vol%,GO@f-CNTs/PDMS composites present the optimal thermal conductivity coefficient(λ,4.00 W·m^(-1)·K^(-1)),about 20 times that of theλof neat PDMS(0.20 W·m^(-1)·K^(-1)),also much higher than theλ(2.44 W·m^(-1)·K^(-1))of GO/f-CNTs/PDMS composites with the same amount of randomly dispersed fillers.Meanwhile,the obtained GO@f-CNTs/PDMS composites have excellent thermal stability,whoseλdeviation is only about 3%after 500 thermal cycles(20-200℃).
基金supported by the National Research Foundation (NRF) of Korea funded by the Ministry of Science and ICT and Future Planning (MSIP) (2016R1E1A1A01943131)
文摘The intensive development of micro-/nanotechnologies offers a new route to construct sophisticated architectures of emerging soft electronics.Among the many classes of stretchable materials,micro-/nanostructured poly(dimethylsiloxane)(PDMS)has emerged as a vital building block based on its merits of flexibility,stretchability,simple processing,and,more importantly,high degrees of freedom of incorporation with other functional materials,including metals and semiconductors.The artificially designed geometries play important roles in achieving the desired mechanical and electrical performances of devices and thus show great potential for applications in the fields of stretchable displays,sensors and actuators as well as in health-monitoring device platforms.Meanwhile,novel lithographic methods to produce stretchable platforms with superb reliability have recently attracted research interest.The aim of this review is to comprehensively summarize the progress regarding micro-/nanostructured PDMS and their promising soft electronic applications.This review is concluded with a brief outlook and further research directions.
基金the National Natural Science Foundation of China (No. 20176030, No. 20276041).
文摘The pervaporation behavior of fermentation broth was investigated experimentally and compared with those started with ethanol mixtures. Ethanol was produced by Saccharomyces cerevisiae utilizing technical grade glucose and recovered by pervaporation using a composite polydimethylsiloxane (PDMS) membrane prepared in our laboratory. Ethanol concentration in fermentation broth decreased to a relatively low level when pervaporation was coupled with fermentation. The more active cells appeared in the fermentation broth, the better the membrane performance was.
基金Contract grant sponsors: Major State Basic Research Projects of China (G1999064800)
文摘Polydimethylsiloxane (PDMS) rubber latex with two sorts of sensitizers, trimethylol propane tri-methacrylate (TMPTMA) and diethylene glycol di-acrylate (DEGDA), was irradiated with γ-rays and electron beams in various conditions. The radiation crosslinking reaction of PDMS occurs in the inner phase of the latex and is relatively isolated from the water phase. Therefore the oxygen and the radicals produced by the radiolysis reaction of water almost have no effect on the crosslinking reaction of polymer. The experimental data correspond with the Charlesby-Pinner relationship in the main. The gelation doses, degree of crosslinking and degradation as well as G values of crosslinking were calculated. From them, the sensitization coefficients were derived to offer a quantitative measurement of the enhancing effect of sensitizer on the radiation crosslinking.
文摘The fabrication of a separation layer on the inner surface of a hollow fiber (HF) substrate to form an HF composite membrane offers exciting opportunities for industrial applications, although challenges remain. This work reports on the fabrication of a polydimethylsiloxane (PDMS) composite membrane on the inner surface of a single-channel or multi-channel ceramic HF via a proposed coating/crossflow approach. The nanostructures and transport properties of the PDMS HF composite membranes were optimized by controlling the polymer concentration and coating time. The morphology, surface chemistry, interfacial adhesion, and separation performance of the membranes were characterized by fieldemission scanning electron microscope (FE-SEM), attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy, the nano-indentation/scratch technique, and pervaporation (PV) recovery of bio-butanol, respectively. The formation mechanism for the deposition of the PDMS layer onto the inner surface of the ceramic HF was studied in detail. The optimized inner surface of the PDMS/ceramic HF composite membranes with a thin and defect-free separation layer exhibited a high flux of ~1800 gm-2h-1 and an excellent separation factor of 35–38 for 1 wt% n-butanol/water mixtures at 60 C. The facile coating/cross-flow methodology proposed here shows great potential for fabricating inner-surface polymer-coated HFs that have broad applications including membranes, adsorbents, composite materials, and more.
文摘A modified solution-diffusion model was established based on Flory-Huggins thermodynamic theory and Fujita's free volume theory. This model was used for description of the mass transfer of removal benzene from dilute aqueous solutions through polydimethylsiloxane (PDMS) membranes. The effect of component concentration on the interaction parameter between components, that of the polymer membrane on the selectivity to benzene, and that of feed concentration and temperature on the permeation flux and separation factor of benzene/water through PDMS membranes were investigated. Calculated pervaporation fluxes of benzene and water were compared with the experimental results and were in good agreement with the experimental data.
基金supported by the National Natural Science Foundation of China (Nos. 22008028, 22102022 and 22166002)the Opening Project of Jiangxi Province Key Laboratory of Polymer Micro/Nano Manufacturing and Devices (PMND202003)+2 种基金Foshan (Southern China) Institute for New Materials (2021AYF25015)State Key Laboratory of Nuclear Resources and Environment of East China University of Technology (NRE202116)the Training Program of National College Students Innovation and Entrepreneurship (202110405009)
文摘Pervaporation(PV)is an emerging separation technique for liquid mixture.Mixed matrix membranes(MMMs)often demonstrate trade-off relationship between separation factor and flux.In this study,by changing the organic linkers(2-methyl imidazolate,imidazole-2-carboxaldehyde,2-ethyl imidazolate),ZIF-8,ZIF-90 and MAF-6 were prepared and filled in polydimethylsiloxane(PDMS)membranes for dealcoholization of 5%(mass)n-butanol solution,and the membranes properties and pervaporation performances were adjusted.Compared with the pure PDMS membrane,the addition of ZIF-8 resulted in a 9%increase in flux(1136 g·m^(-2)·h^(-1))and a 22.5%increase in separation factor(28.3),displaying antitrade-off effect.For the MAF-6/PDMS MMMs(2.0%mass loading),the pervaporation separation index(PSI)and separation factor were 32347 g·m^(-2)·h^(-1) and 58.6 respectively(increased by 34%and 154%in contrast with that of the pure PDMS membrane),and the corresponding permeation flux was 552 g·m^(-2)·h^(-1),presenting great potential in the removal butanol from water.It was deduced that the large aperture size combined with moderate hydrophobicity of metal–organic frameworks(MOFs)favor the concurrent increase in permeability and selectivity.
基金The work was financially supported by the National Basic Research Program of China(No.2005CB623800).
文摘The surface of calcium carbonate(CaCO_3)particles was modified with stearic acid(SA)and the chemical structures of the product were characterized by FT-IR analysis.The interaction between polydimethylsiloxane(PDMS)and CaCO_3 fillers with different surface character was investigated by means of dynamic rheological and bound rubber tests for uncured compounds and mechanical properties measurements for the corresponding vulcanites.The results of dynamic tests indicate that with the increase of SA mass fraction...
基金the National Natural Science Foundation of China(No.50273035)Anhui Provincial Education Department(No.2004kj362zd)are acknowledged.
文摘A novel hydroxypolyether blocked polydimethylsiloxane, poly（ethylene oxide） propyl-b-polydimethylsiloxane-b-propyl poly（ethylene oxide） （PEO-b-PDMS-b-PEO） was synthesized by simple hydrosilation reaction of poly（ethylene glycol） monoallyl ether with α,ω-dihydrogen terminated PDMS （HPDMS）. Fourier transform infrared spectroscopy （FTIR） and IH NMR were used to identify the structure of PEO-b-PDMS-b-PEO and intermediate product HPDMS. Based on the effect investigations of temperature, reactant molar ratio, catalyst and time on the hydrosilation, it was found that the conversion of Si-H bond to SiC bond increased with the increase of catalyst and time, and the reaction completed when the content of catalyst was 22μg/g and the time was 5 h, respectively. Urethane reaction of OH and NCO group confirms that PEO-b-PDMS-b-PEO is more reactive toward to diisocyanate than α,ω-dihydroxylbutyl terminated PDMS.
文摘Block copolymers with different backbone compositions have been prepared by the condensation of dimethylamino terminated poly（dimethylsiloxane） （PDMS） and hydroquinone terminated poly（phthalazinone ether nitrile） （PPEN） in the presence of chlorobenzcne/N-methyl pyrrolidone （NMP） as solvents. The products were characterized by FTIR, ^1H NMR and gel permeation chromatography. Differential scanning calorimetry analysis indicated that the block copolymers showed separated microphase.
基金supported by the National Natural Science Foundation of China(No.20576117 and No.20836007)
文摘Hydrosilylation has been carried out between Si-H terminated polydimethylsiloxanes with narrow molecular weight distribution and protected 3-allyloxy-l,2-propanediol, and after subsequently alcoholyzed, α-{3-[（2,3-dihydroxy）propoxy]propyl}-ω- butyl-polydimethylsiloxanes with varying number of （（Si（CH3）2-O） unit were obtained. At each step, the produced compounds were carefully characterized. The results showed that each step was successfully carried out and target products were achieved.
