Structural and hydrophobic–hydrophilic properties of nanosilica/zirconia alone and with adsorbed PDMS

Sulym, Iryna; Borysenko, M.V.; Goncharuk, E.V.; Terpiłowski, Konrad; Sternik, Dariusz; Chibowski, Emil; Gun’ko, Vladimir M.

doi:10.1016/j.apsusc.2011.08.045

Cited by 27 publications

(30 citation statements)

References 21 publications

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“…This not only facilitates the introduction of polymer with high molecular mass into highly dispersed material but also improves the distribution of macromolecules in the surface layer, as was shown for PDMS-1000 adsorbed onto silica surface from hexane solution [11]. High dispersity of the material achieved via multistage impregnation of silica using high and low molecular mass polysiloxanes [12]. The surface polymeric layer with high contents of the modifying agent can be achieved using a chemical assembly [13].…”

Section: Introductionmentioning

confidence: 97%

“…However, the PDMS conformation can be changed in the adsorption layer depending on the PDMS content. The authors of [12] show that all surface OH groups have interacted with polymer adsorbed from hexane solution (PDMS-1000 or PDMS-20) in content C15 mass%. This boundary value corresponds to the monolayer capacity of silica with a specific surface area (SSA) 300 m 2 g -1 , and the surface layer is denser for the polymer with shorter macromolecules; the modification degree increase did not strongly affect the material hydrophobicity, which achieved the highest value at 20 mass% polymer content.…”

Section: Introductionmentioning

confidence: 99%

“…That is why the study of structural features of the attached polymeric surface layer attracts great attention. The structure of polydimethylsiloxane (PDMS) chain, namely a helix with six Si-O bonds in a cycle [12], decreases the number of contacts with silica surface via hydrogen bonds formed between silanol surface groups and siloxane bridges. However, the PDMS conformation can be changed in the adsorption layer depending on the PDMS content.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

DSC study of silicas with immobilized polysiloxane layer of different architecture

Bolbukh

Koutsoumpis

Georgopoulos

et al. 2016

J Therm Anal Calorim

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Core-shell structured nanocomposites of polydimethylsiloxane with different polymerization degree (PMS100 and PMS50) and polymethylphenylsiloxane (PMPS4) immobilized onto fumed silica nanoparticles were studied by means of differential scanning calorimetry. The polysiloxanes were attached to the particles' surface using thermally stimulated binding and modification in the presence of depolymerization activator-dimethyl carbonate (DMC). Single-and multi-stage processes were applied in order to obtain a different architecture of polymeric layer on the silica nanoparticles surface. The effect of polysiloxane/DMC ratio on phase transitions of obtained polymeric layers was evaluated. The grafting of polydimethylsiloxane at the presence of chain scissor resulted in cross-linking of the attached polymeric layers. When using a multi-step modification with PMPS, a dense crosslinked layer was formed on the silica surface. Unlike the samples obtained by one-step modification with different polymer content, for which the amount of polymer attached to silica surface changes the parameters of the relaxation process in polymeric layer, for composites synthesized using multi-stage modification, a greater influence has the length of the oligomer introduced on first stage. The best results were achieved for composite with PMPS when using on the first stage of modification the PMPS/DMC mixture with low content of depolymerization agent (oligomers with long chain, respectively). A notable increase in the mobility of the polymeric layer was detected due to the formation of isotactic macromolecular chains.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

DSC study of silicas with immobilized polysiloxane layer of different architecture

Bolbukh

Koutsoumpis

Georgopoulos

et al. 2016

J Therm Anal Calorim

View full text Add to dashboard Cite

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“…The precise control of the laser textured surfaces and texture patterns were key factors in determining the potential suitability of textured surfaces for various applications. Structural and hydrophobic-hydrophilic properties of nanosilica/zirconia were studied by Sulym et al [15]. They showed that the surface topology of the particles was important for the hydrophobic state of the surface and nanosilica/zirconia modified by polydimethylsiloxane (PDMS) remained in the powder state with aggregates of primary particles smaller than those of unmodified PDMS surfaces.…”

Section: Introductionmentioning

confidence: 99%

Texture Analysis of Hydrophobic Polycarbonate and Polydimethylsiloxane Surfaces via Persistent Homology

et al. 2017

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Due to recent climate change-triggered, regular dust storms in the Middle East, dust mitigation has become the critical issue for solar energy harvesting devices. One of the methods to minimize and prevent dust adhesion and create self-cleaning abilities is to generate hydrophobic characteristics on surfaces. The purpose of this study is to explore the topological features of hydrophobic surfaces. We use non-standard techniques from topological data analysis to extract morphological features from the AFM images. Our method recovers most of the previous qualitative observations in a robust and quantitative way. Persistence diagrams, which is a summary of topological structures, witness quantitatively that the crystallized polycarbonate (PC) surface possesses spherulites, voids, and fibrils, and the texture height and spherulite concentration increases with the increased immersion period. The approach also shows that the polydimethylsiloxane (PDMS) exactly copied the structures at the PC surface but 80 to 90 percent of the nanofibrils were not copied at PDMS surface. We next extract a feature vector from each persistence diagram to show which experiments hold features with similar variance using principal component analysis (PCA). The K-means clustering algorithm is applied to the matrix of feature vectors to support the PCA result, grouping experiments with similar features.

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“…However, due to high reactivity and moisture sensitivity of above-mentioned modifying agents, purification is often critical for these hydrolyzable precursors. Poly(dimethylsiloxanes) provide a viable and environmentally benign alternative to the chemical functionalization of oxides as they are characterized by high carbon content, hydrophobic properties, thermal stability, chemical inertness, and they are noncorrosive reagents, and generate only water as a byproduct [9][10][11][12][13][14][15][16][17][18][19][20][21]. Despite this fact, the chemisorption of the simplest methylsiloxanes-hexamethyldisiloxane (H 3 C) 3 SiOSi(CH 3 ) 3 on fumed silica surfaces requires the use of very high temperatures (>350 • C) [19,[22][23][24].…”

Section: Introductionmentioning

confidence: 99%

A New Route for Preparation of Hydrophobic Silica Nanoparticles Using a Mixture of Poly(dimethylsiloxane) and Diethyl Carbonate

et al. 2018

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Abstract:Organosilicon layers chemically anchored on silica surfaces show high carbon content, good thermal and chemical stability and find numerous applications as fillers in polymer systems, thickeners in dispersing media, and as the stationary phases and carriers in chromatography. Methyl-terminated poly(dimethylsiloxanes) (PDMSs) are typically considered to be inert and not suitable for surface modification because of the absence of readily hydrolyzable groups. Therefore, in this paper, we report a new approach for surface modification of silica (SiO 2 ) nanoparticles with poly(dimethylsiloxanes) with different lengths of polymer chains (PDMS-20, PDMS-50, PDMS-100) in the presence of diethyl carbonate (DEC) as initiator of siloxane bond splitting. Infrared spectroscopy (IR), elemental analysis (CHN), transmission electron microscopy (TEM), atomic force microscopy (AFM), rotational viscosity and contact angle of wetting were employed for the characterization of the raw fumed silica and modified silica nanoparticles. Elemental analysis data revealed that the carbon content in the grafted layer is higher than 8 wt % for all modified silicas, but it decreases significantly after sample treatment in polar media for silicas which were modified using neat PDMS. The IR spectroscopy data indicated full involvement of free silanol groups in the chemisorption process at a relatively low temperature (220 • C) for all resulting samples. The contact angle studies confirmed hydrophobic surface properties of the obtained materials. The rheology results illustrated that fumed silica modified with mixtures of PDMS-x/DEC exhibited thixotropic behavior in industrial oil (I-40A), and exhibited a fully reversible nanostructure and shorter structure recovery time than nanosilicas modified with neat PDMS. The obtained results from AFM and TEM analysis revealed that the modification of fumed silica with mixtures of PDMS-20/DEC allows obtaining narrow particle size distribution with uniform dispersity and an average particle size of 15-17 nm. The fumed silica nanoparticles chemically modified with mixtures of PDMS-x/DEC have potential applications such as nanofillers of various polymeric systems, thickeners in dispersing media, and additives in coatings.

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Structural and hydrophobic–hydrophilic properties of nanosilica/zirconia alone and with adsorbed PDMS

Cited by 27 publications

References 21 publications

DSC study of silicas with immobilized polysiloxane layer of different architecture

DSC study of silicas with immobilized polysiloxane layer of different architecture

Texture Analysis of Hydrophobic Polycarbonate and Polydimethylsiloxane Surfaces via Persistent Homology

A New Route for Preparation of Hydrophobic Silica Nanoparticles Using a Mixture of Poly(dimethylsiloxane) and Diethyl Carbonate

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