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Surface Chemistry of Nanohybrids with Fumed Silica Functionalized by Polydimethylsiloxane/Dimethyl Carbonate Studied Using 1H, 13C, and 29Si Solid-State NMR Spectroscopy. Molecules 2021; 26:molecules26195974. [PMID: 34641517 PMCID: PMC8512228 DOI: 10.3390/molecules26195974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 09/26/2021] [Accepted: 09/28/2021] [Indexed: 11/17/2022] Open
Abstract
The investigation of molecular interactions between a silica surface and organic/inorganic polymers is crucial for deeper understanding of the dominant mechanisms of surface functionalization. In this work, attachment of various depolymerized polydimethylsiloxanes (PDMS) of different chain lengths, affected by dimethyl carbonate (DMC), to silica nanoparticles pretreated at different temperatures has been studied using 29Si, 1H, and 13C solid-state NMR spectroscopy. The results show that grafting of different modifier blends onto a preheated silica surface depends strongly on the specific surface area (SSA) linked to the silica nanoparticle size distributions affecting all textural characteristics. The pretreatment at 400 °C results in a greater degree of the modification of (i) A-150 (SSA = 150 m2/g) by PDMS-10/DMC and PDMS-1000/DMC blends; (ii) A-200 by PDMS-10/DMC and PDMS-100/DMC blends; and (iii) A-300 by PDMS-100/DMC and PDMS-1000/DMC blends. The spectral features observed using solid-state NMR spectroscopy suggest that the main surface products of the reactions of various depolymerized PDMS with pretreated nanosilica particles are the (CH3)3SiO-[(CH3)2SiO-]x fragments. The reactions occur with the siloxane bond breakage by DMC and replacing surface hydroxyls. Changes in the chemical shifts and line widths, as shown by solid-state NMR, provide novel information on the whole structure of functionalized nanosilica particles. This study highlights the major role of solid-state NMR spectroscopy for comprehensive characterization of functionalized solid surfaces.
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Mahtabani A, La Zara D, Anyszka R, He X, Paajanen M, van Ommen JR, Dierkes W, Blume A. Gas Phase Modification of Silica Nanoparticles in a Fluidized Bed: Tailored Deposition of Aminopropylsiloxane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:4481-4492. [PMID: 33823592 PMCID: PMC8154872 DOI: 10.1021/acs.langmuir.0c03647] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 03/23/2021] [Indexed: 06/12/2023]
Abstract
Functionalized nanoparticles have various applications, for which grafting of a chemical moiety onto the surface to induce/improve certain properties is needed. When incorporated in polymeric matrices, for instance, the modified nanoparticles can alter the interfacial characteristics leading to improvements ofthe macroscopic properties of the nanocomposites. The extent of these improvements is highly dependent on the thickness, morphology and conformity of the grafted layer. However, the common liquid-phase modification methods provide limited control over these factors. A novel gas-phase modification process was utilized, with 3-aminopropyltriethoxysilane (APTES) as precursor, to chemically deposit amino-terminated organic layers on fumed silica nanoparticles in a fluidized bed. A self-limiting surface saturation was achieved when the reaction was done at 200 °C. With this self-limiting feature, we were able to graft multiple layers of aminopropylsiloxane (APS) onto the silica nanoparticles using water as the coreactant. The feasibility of this process was analyzed using thermogravimetric analysis (TGA), diffuse reflectance IR Fourier transform spectroscopy (DRIFTS), X-ray photoelectron spectroscopy (XPS), and elemental analysis (EA). By altering the number of APTES/water cycles, it was possible to control the thickness and conformity of the deposited aminopropylsiloxane layer. This novel approach allows to engineer the surface of nanoparticles, by introducing versatile functionalized layers in a controlled manner.
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Affiliation(s)
- Amirhossein Mahtabani
- University
of Twente, Faculty of Engineering Technology, Department of Mechanics of Solids, Surfaces & Systems
(MS3), Chair of Elastomer Technology and Engineering, P.O. Box 217, 7500 Enschede, The Netherlands
| | - Damiano La Zara
- Department
of Chemical Engineering, Delft University
of Technology, 2629 HZ Delft, The Netherlands
| | - Rafał Anyszka
- University
of Twente, Faculty of Engineering Technology, Department of Mechanics of Solids, Surfaces & Systems
(MS3), Chair of Elastomer Technology and Engineering, P.O. Box 217, 7500 Enschede, The Netherlands
| | - Xiaozhen He
- University
of Twente, Faculty of Engineering Technology, Department of Mechanics of Solids, Surfaces & Systems
(MS3), Chair of Elastomer Technology and Engineering, P.O. Box 217, 7500 Enschede, The Netherlands
| | - Mika Paajanen
- VTT
Technical Research Centre of Finland Ltd, P.O. Box 1001, FI-33014 Tampere, Finland
| | - J. Ruud van Ommen
- Department
of Chemical Engineering, Delft University
of Technology, 2629 HZ Delft, The Netherlands
| | - Wilma Dierkes
- University
of Twente, Faculty of Engineering Technology, Department of Mechanics of Solids, Surfaces & Systems
(MS3), Chair of Elastomer Technology and Engineering, P.O. Box 217, 7500 Enschede, The Netherlands
| | - Anke Blume
- University
of Twente, Faculty of Engineering Technology, Department of Mechanics of Solids, Surfaces & Systems
(MS3), Chair of Elastomer Technology and Engineering, P.O. Box 217, 7500 Enschede, The Netherlands
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Protsak I, Gun’ko V, Morozov Y, Henderson IM, Zhang D, Yinjun Z, Turov V. Intermediates of tris(pentafluorophenyl)borane and dimethyl carbonate pave the way for deeper organosiloxane depolymerization reactions. Polym J 2021. [DOI: 10.1038/s41428-020-00452-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Protsak I, Gun’ko VM, Henderson IM, Pakhlov EM, Sternik D, Le Z. Nanostructured Amorphous Silicas Hydrophobized by Various Pathways. ACS OMEGA 2019; 4:13863-13871. [PMID: 31497703 PMCID: PMC6714511 DOI: 10.1021/acsomega.9b01508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/31/2019] [Indexed: 06/10/2023]
Abstract
Various nanostructured amorphous silicas [fumed silicas such as crude (A-300), hydro-compacted (cA-300, TS 100), and precipitated silica Syloid 244] were modified by different polydimethylsiloxanes such as PDMS5, PDMS100, PDMS200, PDMS1000, and PDMS12500 (the label numbers show the viscosity (η) values) using dimethyl carbonate (DMC) as a siloxane-bond-breaking reagent. In addition, hexamethyldisilazane was used to modify fumed silica cA-300. The nanocomposites were characterized using microscopy, infrared spectroscopy, thermodesorption, nitrogen adsorption-desorption, solid-state NMR spectroscopy, small-angle X-ray scattering, and zeta-potential methods. It was found that the morphological, textural, and structural characteristics of silicas grafted with PDMS depend strongly not only on the type and content of the polymers used but also on the organization of nonporous nanoparticles (NPNP) in secondary structures (aggregates of NPNP and agglomerated aggregates, ANPNP), as well on the reaction temperature (T r). Specifically, we determined that ANPNP with a macro/mesoporous character are favorable for the effective modification of the silicas studied with short polymers and no DMC addition but at higher temperatures or for a longer silicone polymer with the presence of DMC and at lower temperatures. In particular, the PDMS/DMC-modified silicas are of great interest from a practical point of view because they remain in a dispersed state with no strong compaction of the secondary structures after modification, and this corresponds to a better distribution of the modified nanoparticles in polymeric or other matrices.
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Affiliation(s)
- Iryna
S. Protsak
- College
of Environment, Zhejiang University of Technology, Hangzhou 310014, China
- College
of Science, Zhejiang University of Technology, Hangzhou 310023, China
| | - Volodymyr M. Gun’ko
- Chuiko
Institute of Surface Chemistry of NAS of Ukraine, Kiev 03164, Ukraine
| | - Ian M. Henderson
- Omphalos
Bioscience, LLC, Albuquerque 87110, New Mexico, United States
| | - Evgeniy M. Pakhlov
- Chuiko
Institute of Surface Chemistry of NAS of Ukraine, Kiev 03164, Ukraine
| | | | - Zichun Le
- College
of Science, Zhejiang University of Technology, Hangzhou 310023, China
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Protsak I, Gun'ko VM, Turov VV, Krupska TV, Pakhlov EM, Zhang D, Dong W, Le Z. Nanostructured Polymethylsiloxane/Fumed Silica Blends. MATERIALS 2019; 12:ma12152409. [PMID: 31357739 PMCID: PMC6695803 DOI: 10.3390/ma12152409] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 11/16/2022]
Abstract
Polymethylsiloxane (PMS) and fumed silica, alone and in a blended form (1:1 w/w), differently pretreated, hydrated, and treated again, were studied using TEM and SEM, nitrogen adsorption-desorption, 1H MAS and 29Si CP/MAS NMR spectroscopy, infrared spectroscopy, and methods of quantum chemistry. Analysis of the effects of adding water (0-0.5 g of water per gram of solids) to the blends while they are undergoing different mechanical treatment (stirring with weak (~1-2 kg/cm2) and strong (~20 kg/cm2) loading) show that both dry and wetted PMS (as a soft material) can be grafted onto a silica surface, even with weak mechanical loading, and enhanced mechanical loading leads to enhanced homogenization of the blends. The main evidence of this effect is strong nonadditive changes in the textural characteristics, which are 2-3 times smaller than additive those expected. All PMS/nanosilica blends, demonstrating a good distribution of nanosilica nanoparticles and their small aggregates in the polymer matrix (according to TEM and SEM images), are rather meso/microporous, with the main pore-size distribution peaks at R > 10 nm in radius and average <RV> values of 18-25 nm. The contributions of nanopores (R < 1 nm), mesopores (1 nm < R < 25 nm), and macropores (25 nm < R < 100 nm), which are of importance for studied medical sorbents and drug carriers, depend strongly on the types of the materials and treatments, as well the amounts of water added. The developed technique (based on small additions of water and controlled mechanical loading) allows one to significantly change the morphological and textural characteristics of fumed silica (hydrocompaction), PMS (drying-wetting-drying), and PMS/A-300 blends (wetting-drying under mechanical loading), which is of importance from a practical point of view.
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Affiliation(s)
- Iryna Protsak
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
- College of Science, Zhejiang University of Technology, Hangzhou 310023, China
| | - Volodymyr M Gun'ko
- Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, Kyiv 03164, Ukraine
| | - Volodymyr V Turov
- Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, Kyiv 03164, Ukraine
| | - Tetyana V Krupska
- Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, Kyiv 03164, Ukraine
| | - Eugeniy M Pakhlov
- Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, Kyiv 03164, Ukraine
| | - Dong Zhang
- Department of Chemical & Biomolecular Engineering, University of Akron, Akron, OH 44325, USA
| | - Wen Dong
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Zichun Le
- College of Science, Zhejiang University of Technology, Hangzhou 310023, China
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Protsak IS, Morozov YM, Dong W, Le Z, Zhang D, Henderson IM. A 29Si, 1H, and 13C Solid-State NMR Study on the Surface Species of Various Depolymerized Organosiloxanes at Silica Surface. NANOSCALE RESEARCH LETTERS 2019; 14:160. [PMID: 31089904 PMCID: PMC6517472 DOI: 10.1186/s11671-019-2982-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/15/2019] [Indexed: 05/24/2023]
Abstract
Three poly(organosiloxanes) (hydromethyl-, dimethyl-, and epoxymethylsiloxane) of different chain lengths and pendant groups and their mixtures of dimethyl (DMC) or diethyl carbonates (DEC) were applied in the modification of fumed silica nanoparticles (FSNs). The resulting modified silicas were studied in depth using 29Si, 1H, and 13C solid-state NMR spectroscopy, elemental analysis, and nitrogen adsorption-desorption (BET) analysis. The obtained results reveal that the type of grafting, grafting density, and structure of the grafted species at the silica surface depend strongly on the length of organosiloxane polymer and on the nature of the "green" additive, DMC or DEC. The spectral changes observed by solid-state NMR spectroscopy suggest that the major products of the reaction of various organosiloxanes and their DMC or DEC mixtures with the surface are D (RR'Si(O0.5)2) and T (RSi(O0.5)3) organosiloxane units. It was found that shorter methylhydro (PMHS) and dimethylsiloxane (PDMS) and their mixtures with DMC or DEC form a denser coverage at the silica surface since SBET diminution is larger and grafting density is higher than the longest epoxymethylsiloxane (CPDMS) used for FSNs modification. Additionally, for FSNs modified with short organosiloxane PMHS/DEC and also medium organosiloxane PDMS/DMC, the dense coverage formation is accompanied by a greater reduction of isolated silanols, as shown by solid-state 29Si NMR spectroscopy, in contrast to reactions with neat organosiloxanes. The surface coverage at FSNs with the longest siloxane (CPDMS) greatly improves with the addition of DMC or DEC. The data on grafting density suggest that molecules in the attached layers of FSNs modified with short PMHS and its mixture of DMC or DEC and medium PDMS and its mixture of DMC form a "vertical" orientation of the grafted methylhydrosiloxane and dimethylsiloxane chains, in contrast to the reaction with PDMS/DEC and epoxide methylsiloxane in the presence of DMC or DEC, which indicates a "horizontal" chain orientation of the grafted methyl and epoxysiloxane molecules. This study highlights the major role of solid-state NMR spectroscopy for comprehensive characterization of solid surfaces.
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Affiliation(s)
- Iryna S. Protsak
- College of Environment, Zhejiang University of Technology, Hangzhou, 310014 China
- College of Science, Zhejiang University of Technology, Hangzhou, 310023 China
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, Hangzhou, 310014 China
| | - Yevhenii M. Morozov
- College of Science, Zhejiang University of Technology, Hangzhou, 310023 China
- Institute for Information Recording of NAS of Ukraine, Kiev, 03113 Ukraine
| | - Wen Dong
- College of Environment, Zhejiang University of Technology, Hangzhou, 310014 China
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, Hangzhou, 310014 China
| | - Zichun Le
- College of Science, Zhejiang University of Technology, Hangzhou, 310023 China
| | - Dong Zhang
- College of Materials Science & Engineering, Zhejiang University of Technology, Hangzhou, 310014 China
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Gun'ko VM, Turov VV, Krupska TV, Protsak IS, Borysenko MV, Pakhlov EM. Polymethylsiloxane alone and in composition with nanosilica under various conditions. J Colloid Interface Sci 2019; 541:213-225. [PMID: 30690265 DOI: 10.1016/j.jcis.2019.01.102] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 02/08/2023]
Abstract
Disperse polymethylsiloxane (PMS) alone and in a mixture with highly disperse nanosilica A-300 was studied as a dry powder and a hydrogel located in various dispersion media (air, chloroform alone and with addition of trifluoroacetic acid) using low-temperature 1H NMR spectroscopy, cryoporometry, thermogravimetry, nitrogen adsorption, microscopy, infrared spectroscopy, and quantum chemistry. The powders of dried PMS and PMS/A-300 can be easily rehydrated upon strong stirring with added water. The slurry properties depend on mechanical treatment features due to stronger compaction of the secondary structures with increasing mechanical loading. The organization of bound water (at a constant hydration degree h = 1 g/g) depends strongly on the dispersion media (because chloroform can displace water from narrow interparticle voids into broader ones or into pores inaccessible for larger CDCl3 molecules) and mechanical loading reorganizing aggregates of PMS and A-300 nanoparticles (<1 μm in size) and agglomerates (>1 μm) of aggregates. The PMS/nanosilica blends could be of interest from a practical point of view due to additional control of the textural and structural characteristics determining efficiency of sorbents with respect to low- and high-molecular weight compounds depending on the dispersion media that is of importance, e.g., for medical applications.
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Affiliation(s)
- V M Gun'ko
- Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164, Ukraine.
| | - V V Turov
- Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164, Ukraine
| | - T V Krupska
- Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164, Ukraine
| | - I S Protsak
- Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164, Ukraine
| | - M V Borysenko
- Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164, Ukraine
| | - E M Pakhlov
- Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164, Ukraine
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