Aminopropylisobutyl Polyhedral Oligomeric Silsesquioxane Research Articles

Polyurea/Aminopropyl Isobutyl Polyhedral Oligomeric Silsesquioxane-Functionalized Graphene Nanoplatelet Nanocomposites for Force Protection Applications.

Herein, the development of new nanocomposite systems is reported based on one-part polyurea (PU) and aminopropyl isobutyl polyhedral oligomeric silsesquioxane (POSS)-functionalized graphene nanoplatelets (GNP-POSS) as compatible nanoreinforcements with the PU resin. GNP-POSS was effectively synthesized via a two-step synthesis protocol, including ultrasonication-assisted reaction and precipitation, and carefully characterized with respect to its chemical and crystalline structure, morphology, and thermal stability. FTIR and XPS spectroscopy analyses revealed that POSS interacts with the residual oxygen moieties of the GNPs through both covalent and noncovalent bonding. The X-ray diffraction pattern of GNP-POSS further revealed that the crystallinity of the GNPs was not altered after their functionalization with POSS. GNP-POSS was successfully incorporated in PU at contents of 1, 3, 5, and 10 wt % to yield PU/GNP-POSS nanocomposite films. An ATR-FTIR analysis of these films confirmed the presence of strong interfacial interactions between the urea groups of PU and the GNP-POSS functionalities. Moreover, the PU/GNP-POSS nanocomposite films exhibited enhanced thermal stability and mechanical properties compared to those of the neat PU film. The quasi-static tensile testing of the PU/GNP-POSS samples revealed remarkable enhancements in the tensile strength (from 7.9 for the neat PU to 25.1 MPa for PU/GNP-POSS) and Young's modulus (238-617 MPa), while elongation at break and toughness also showed 14 and 125% improvements, respectively. Finally, the effects of GNP-POSS content on the morphological, quasistatic tensile, and high-strain-rate dynamic behavior of the PU/GNP-POSS nanocomposite films were also investigated. Overall, the tests performed using a split-Hopkinson pressure bar setup revealed a large increase in the film strength (from 147.6 for the neat PU film to 199 MPa for the PU/GNP-POSS film) and a marginal increase in the energy density of the film (38.1-40.8 kJ/m3). These findings support the suitability of the PU/GNP-POSS nanocomposite films for force protection applications.

Liquid crystal epoxy composites based on functionalized boron nitride: Synthesis and thermal properties

AbstractA composite was prepared by in‐situ polymerization of liquid crystal epoxy (LCE4) with a low dielectric and high thermal conductivity boron nitride (BN) filler, which the filler (f‐BN) was surface‐functionalized by γ‐glycidoxypropyltrimethoxysilane (KH560) and aminopropylisobutyl polyhedral oligomeric silsesquioxane (NH2‐POSS). The surface‐functionalized BN was more uniformly dispersed in LCE4, which improved the interfacial compatibility between inorganic and organic phases. Compared with pure LCE4, KH560, and NH2‐POSS modified f‐BN/LCE4 composites exhibited a higher glass transition temperature, better thermal stability, and higher thermal conductivity. For example, when the f‐BN content reached 30 wt%, the energy storage modulus of the composite increased to 2580 MPa, and the glass transition temperature was 103°C. The thermal conductivity of this 30 wt% f‐BN composite was 0.48 W m−1 K−1, 128.6% higher than that of pure LCE4. In addition, thermal stability, low hygroscopicity, and dielectric properties of the composites were characterized and analyzed to explore the application prospects of f‐BN/LCE4 composites in electronic packaging and in high‐performance microelectronic devices.

Rigid POSS intercalated graphene oxide membranes with hydrophilic/hydrophobic heterostructure for efficient pervaporation desalination

Graphene oxide (GO) membranes exhibit fascinating properties in pervaporation desalination due to the unimpeded water permeation in two-dimensional (2D) interlaminar channels. The precise construction of interlayer mass transfer nanochannels and regulation of their microenvironment are crucial to break through the trade-off effect of pervaporation desalination performance and achieve high stability of GO membranes. Herein, aminopropylisobutyl polyhedral oligomeric silsesquioxane (NH2-POSS) was intercalated into GO interlayers with glutaraldehyde as crosslinking reagent to fabricate POSS@GO hybrid membranes. The intercalation of POSS into GO interlayers provided enlarged interlayer spacing for water permeation and appropriate steric hindrance for ion rejection as well as better swelling resistance, which promoted both of water permeation flux and salt rejection of GO membranes. The optimized POSS@GO hybrid membrane displayed an outstanding water flux of 112.7 kg/(m2·h) and 99.98 % salt rejection in desalinating 3.5 wt% NaCl solution at 80 °C. Benefiting from the formation of hydrophilic/hydrophobic heterostructure and crosslinking with glutaraldehyde, POSS@GO hybrid membranes could toughly resist membrane swelling and exhibited stable and reliable desalination performance. Desirable stability of pervaporation desalination performance was acquired in the 24 h long-term separation experiment at 80 °C. The study might provide some new insight in designing high-efficiency 2D laminar membranes for pervaporation desalination by elaborate regulation of transport channel size without sacrificing interlayer spacing based on the construction of appropriate hydrophilic/hydrophobic heterostructure.

Design on the corrosion protection of eco-friendly and multifunctional polyhedral oligomeric silsesquioxane functionalized graphene oxide reinforced waterborne polyurethane

This paper explored that the novel waterborne polyurethane (WPU) composite coatings with superior corrosion protection performance was fabricated via intercalating functionalized graphene oxide (GO). The eco-friendly and superhydrophobic aminoethyl aminopropyl isobutyl polyhedral oligomeric silsesquioxane (POSS-NH-NH2) was applied to modify GO via facile one-step chemical grafting. Several analyses such as FT-IR, XRD, Raman, and SEM were performed to verify the successful graft of POSS-NH-NH2 into the GO. Sequentially, the WPU and WPU composite coatings containing GO and functional graphene oxide (PNNG) nanoparticles were prepared and applied on Q235 steel with a thickness of 55 ± 5 µm. The corrosion protection performance of coatings was investigated by electrochemical impedance spectroscopy and potentiodynamic polarization. The results highlighted that well-dispersed and hydrophobic PNNG nanoparticle remarkably enhanced the corrosion protection performance of WPU. In detail, the protection efficiency of WPU composite coatings with 0.1 wt% PNNG reached 99.79% relative to pure WPU. After 21 days’ immersions in 3.5 wt% NaCl aqueous solution, the ǀZ|f=0.01Hz of WPU decreased to 1.96 × 105 Ω cm2 from 1.52 × 107 Ω cm2. However, the ǀZ|f=0.01Hz of WPU with 0.1 wt% PNNG was 1.48 × 108 Ω cm2 after 180 days’ immersions, which was still about 3 orders of magnitude higher than that of WPU.

Amino-functionalized POSS nanocage-intercalated titanium carbide (Ti3C2Tx) MXene stacks for efficient cesium and strontium radionuclide sequestration

In this work, we prepared two-dimensional (2D) stack-structured aminopropylIsobutyl polyhedral oligomeric silsesquioxane (POSS-NH2) intercalated titanium carbide (Ti3C2Tx) MXene material (Ti3C2Tx/POSS-NH2) using a post-intercalation strategy as a potential adsorbent for the removal of cesium (Cs+) and strontium (Sr2+) ions from aqueous solutions. Ti3C2Tx/POSS-NH2 exhibited unprecedented adsorption capacities of 148 and 172 mg g−1 for Cs+ and Sr2+ ions, respectively. Batch adsorption experimental data well fitted the Freundlich isotherm model, which revealed multilayer adsorption of Cs+ and Sr2+ ions onto heterogeneous –OH, –F, –O, and –NH2 adsorption sites of Ti3C2Tx/POSS-NH2 with different energies. Ti3C2Tx/POSS-NH2 exhibited rapid Cs+/Sr2+ ions adsorption kinetics and attained equilibrium within 30 min. Also, Ti3C2Tx/POSS-NH2 exhibited recyclable capability over three cycles and remarkable selectivities of 89% and 93% for Cs+ and Sr2+ ions, respectively, in the presence of co-existing mono- and divalent cations. We suggest the high adsorption capacity of Ti3C2Tx/POSS-NH2 might be due to the synergistic effects of (i) increased inter-lamellar distance between Ti3C2Tx galleries due to POSS-NH2 intercalation, enabling diffusion and encapsulation of large numbers of Cs+/Sr2+ ions, (ii) strong complexation of amine (–NH2) groups of POSS-NH2 with Cs+/Sr2+ ions, and (iii) the presence of large numbers of heterogeneous surface functional groups (e.g., –OH, –F, and –O), which resulted in the adsorptions of Cs+/Sr2+ ions through electrostatic, ion exchange, and surface complexation mechanisms. Given the extraordinary adsorption capacities observed, intercalation appears to be a promising strategy for the effective removal of radioactive Cs+ and Sr2+ ions from aqueous media.

Thioxanthone attached polyhedral oligomeric silsesquioxane (POSS) nano-photoinitiator for preparation of PMMA hybrid networks in air atmosphere

2-(9-Oxo-9H-thioxanthene-2-yloxy)-N-(3-silsesquioxanylpropyl) acetamide was synthesized with 2-(carboxymethoxy) thioxanthone and aminopropylisobutyl POSS as precursors. Absorption characteristics of 2-(9-Oxo-9H-thioxanthene-2-yloxy)-N-(3-silsesquioxanylpropyl) acetamide is similar to the thioxanthone, even its molar absorptivity is much higher than bare precursor thioxanthone. The one-component nature of this nano-photoinitiator allowed us to use it as a photoinitiator even in the air atmosphere. Initiation mechanism of 2-(9-oxo-9H-thioxanthene-2-yloxy)-N-(3-silsesquioxanylpropyl) acetamide is based on intramolecular hydrogen abstraction and resulted alkyl radical which initiate polymerization. Intramolecular hydrogen abstraction of 2-(9-oxo-9H-thioxanthene-2-yloxy)-N-(3-silsesquioxanylpropyl) acetamide ends up as the covalent linkage of POSS structure to the polymer. The important contribution of incorporation and good dispersion of POSS in poly(methyl methacrylate) matrices were observed as an improve in thermal stability and led to the formation of robust polymer/filler network. Poly(methyl methacrylate) hybrid network prepared with 2-(9-oxo-9H-thioxanthene-2-yloxy)-N-(3-silsesquioxanylpropyl) and aminopropylisobutyl POSS / 2-(carboxymethoxy) thioxanthone and scanning electron microscopy images of casts film surfaces presented two different views. First formulation displayed smaller and more homogeneous pores. Second formulation, which contains two component system, led to disordered porous structures.

Effect of Alkyl Chain Length in POSS Nanocage on Non-Isothermal Crystallization Behavior of PCL/Amino-POSS Nanocomposites.

The study of the non-isothermal crystallization behavior of polymers is of great importance due to the effect of degree of crystallinity and crystallization process on the polymer properties. The effect of aminopropylisobutyl polyhedral oligomeric silsesquioxane (APIBPOSS) and aminopropylisooctyl polyhedral oligomeric silsesquioxane (APIOPOSS) on poly(ε-caprolactone) (PCL) crystallization is studied by differential scanning calorimetry (DSC) under non-isothermal conditions and polarized optical microscopy (POM). The crystallization kinetics is analyzed using the Avrami and Mo models, and effective activation energies are evaluated by the Friedman isoconversional method. The results show that the compatibility between polyhedral oligomeric silsesquioxanes (POSS) and PCL and POSS loading affect the crystallization process. A higher crystallization temperature, a narrower size distribution of crystallite, and a faster crystallization rate are obtained in the presence of all the studied contents of APIBPOSS and at lower contents of APIOPOSS. At APIOPOSS contents higher than 2 wt %, the crystallization temperature is lowered, the size distribution of crystallite is broadened, and the crystallization process is retarded. The presence of POSS leads to an increase in the number of nucleation sites, and a reduction in the size of the crystallite and the overall degree of crystallinity, as a result of the confinement of PCL chains caused by POSS nanoparticles.

Chemically Synthesized Carbon Nanorods with Dual Polarized Emission.

We realized the synthesis of carbon nanorods-monodisperse colloidal particles with a length of 50 nm and a width of 20 nm-which can be considered an addition to the family of light-emitting carbon-based nanostructures. Their anisotropic shape is determined by the use of the surfactant aminopropylisobutyl polyhedral oligomeric silsesquioxane, and their optical properties originate from domains of polycyclic aromatic hydrocarbons incorporated within an inorganic framework. The nanorods show dual polarized emission with a quantum yield of 15-20% and emission anisotropy of ∼0.3, which changes from blue (460 nm) to yellow (565 nm) depending on the excitation wavelength. These carbon nanorods expand the range of light-emitting carbon nanomaterials available for optoelectronic and biolabeling applications.

Holographic polymer nanocomposites with ordered structures and improved electro-optical performance by doping POSS

Holographic polymer nanocomposites containing the liquid crystal (LC) have garnered a great deal of attention primarily because of their unique electric-switchable optical properties. Herein, three types of polyhedral oligomeric silsesquioxane (POSS) are doped into the holographic polymer nanocomposites to tune their ordered structure and electro-optical performance. These POSS dopants are methacryl POSS with eight reactive double bonds, methacrylisobutyl POSS with one reactive double bond, and aminopropylisobutyl POSS with nonreactive groups. Interestingly, methacryl POSS is primarily chemically bonded to the polymer network within the constructive regions, which deteriorates the diffraction efficiency and electro-optical performance due to the depressed ordered structures. In contrast, methacrylisobutyl POSS displays a negligible effect on the diffraction efficiency and electro-optical performance while significantly improving the thermostability of holographic polymer nanocomposites, although it is also chemically linked to the polymer network within the constructive regions. Distinctively, aminopropylisobutyl POSS mainly locates in the destructive regions and clearly improves the electro-optical performance and thermostability of holographic polymer nanocomposites.

Mechanistic Insights from Functional Group Exchange Surface Passivation: A Combined Theoretical and Experimental Study

Four different functional groups including amino (−NH2), phosphine (−PH2), hydroxyl (−OH), and thiol (−SH) were combined with POSS (polyhedral oligomeric silsesquioxane) molecules to investigate how functional groups affect the surface passivation of POSS systems. Results from density-functional theory (DFT) calculations indicate that functional group amino (−NH2) with adsorption energy 86 (56) kJ mol–1 is consistently better than that of thiol (−SH) with adsorption energy 68 (43) kJ mol–1 for different passivation mechanisms. Theoretical studies on the analogous POSS–OH and POSS–PH2 systems show similar adsorption energies. Two of the systems were also investigated experimentally; aminopropyl isobutyl POSS (POSS–NH2) and mercaptopropyl isobutyl POSS (POSS–SH) were applied as passivation materials for MAPbI3 (MA = methylammonium) perovskite and (FA)0.85(MA)0.15Pb(I3)0.85(Br3)0.15 (FA = formamidinium) perovskite films. The same conclusion was drawn based on the results from contact angle studies, X-ray dif...

Enhanced thermal conductivities and decreased thermal resistances of functionalized boron nitride/polyimide composites

Fluorine-containing polyimide (PI) with low dielectric constant (ε) value was firstly synthesized by a polycondensation reaction of 4, 4-(hexafluoroisopropyl) diphthalic anhydride (6FDA), 1, 3, 4-triphenyldiether diamine (APB) and 1, 3-bis(3-aminopropyl) tetramethyldisiloxane (GAPD). γ-glycidoxypropyltrimethoxysilane (KH-560) and aminopropylisobutyl polyhedral oligomeric silsesquioxane (NH2-POSS) were synchronously performed to functionalize the surface of boron nitride (f-BN) fillers, which were then utilized as thermally conductive fillers to fabricate the corresponding f-BN/PI composites. NH2-POSS was successfully grafted on the surface of BN fillers. All the f-BN/PI composites presented better thermal conductivities, dielectric and thermal properties than those of BN/PI composites at the same addition of BN fillers. The obtained thermal conductivity coefficient (λ) of the f-BN/PI composites with 30 wt% f-BN was 0.71 W/mK, higher than that of BN/PI composites with 30 wt% BN (λ of 0.69 W/mK). Modified Hashin-Shtrikman model demonstrated that f-BN possessed relatively lower thermal resistance with PI matrix. Meantime, the corresponding ε and dielectric loss tangent (tanδ) value of the f-BN/PI composites was decreased to 3.32 and 0.004, respectively, lower than that of BN/PI composites with 30 wt% BN (ε of 3.77 and tanδ of 0.007). Moreover, the corresponding heat resistance index (THRI) and glass transition temperature (Tg) of the f-BN/PI composites was further enhanced to 280.2 °C and 251.7 °C, respectively.

Amphiphilic tadpole-shaped POSS-poly(glycerol methacrylate) hybrid polymers: synthesis and self-assembly

A new series of well-defined amphiphilic hybrid polymers of tadpole-shaped architecture with polyhedral oligomeric silsesquioxane (POSS) nanocage as the hydrophobic head and poly(glycerol methacrylate) (PGMA) as the hydrophilic tail (POSS-PGMA) has been synthesized via atom transfer radical polymerization (ATRP). The aminopropylIsobutyl POSS, a monofunctional POSS nanocage, was transformed into ATRP initiator by treating with 2-bromoisobutyrylbromide. The POSS-PGMA was achieved in two steps. First, solketal methacrylate (SMA) (the precursor monomer for GMA), synthesized by reacting solketal with methacryloyl chloride, was polymerized under typical ATRP conditions with THF as the solvent at 40 °C, employing the synthesized POSS based initiator, and CuCl/N,N,N,N,N-pentamethyldiethylenetriamine as the catalyst system. The size exclusion chromatography (SEC) chromatograms reveal monomodal molecular weight distributions and narrow polydispersity indices; suggesting that well-defined tadpole-shaped hybrid polymers have been achieved. This further confirms that the monofunctional POSS initiator is able to affectively polymerize SMA in a controlled fashion under ATRP conditions. In the second step, the obtained POSS-PSMA was transformed into amphiphilic POSS-PGMA by acid hydrolysis. The successful transformation could be verified by 1H NMR and FTIR spectroscopy. Finally, because of the amphiphilic nature, the obtained POSS-PGMA could self-assemble when dispersed in water as confirmed by measuring the critical aggregation concentration (CAC) by fluorescence spectroscopy, using pyrene as the fluorescence probe. The CAC was found to increase with increasing the PGMA chain length. The large hydrodynamic size of the self-assembled structures, as determined by the laser light scattering data, however, suggests that the aggregates are not of typical core-shell type micelles.

Improvement of anticorrosion ability of epoxy matrix in simulate marine environment by filled with superhydrophobic POSS-GO nanosheets.

Super-hydrophobicity polyhedral oligomeric silsesquioxane-modified graphene oxide (POSS-GO) was synthesized by one-step reaction between graphene oxide (GO) and aminopropylisobutyl polyhedral oligomeric silsesquioxane (POSS-NH2). Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra indicated that the POSS were successfully connected to the edge and surface of GO nanosheets. Scanning probe microscope (SPM) and transmission electron microscope (TEM) images demonstrated that the POSS-GO with a thickness of 1.58 nm presented a stably dispersion in anhydrous ethanol. Results from electrochemical behaviors showed that the proper incorporation of POSS-GO could availably improve the anticorrosion ability of epoxy based coatings in simulate marine environment (3.5 wt% NaCl solution). The good dispersion of POSS-GO helped to fill the original defect and enhanced the complication of penetration path. The super-hydrophobicity of POSS-GO was beneficial to the reduction of actual contact zone. The synergistic effect of good dispersion and super-hydrophobicity promoted the enhancement of anticorrosion ability for composite coatings.

Thermal stability and mechanical properties of hybrid materials based on nitrocellulose grafted by aminopropylisobutyl polyhedral oligomeric silsesquioxane

The need for improvement in nitrocellulose (NC) storage safety and convenience of application requires an increase in NC thermal stability and enhancement of its mechanical properties. To this aim, hybrid materials were synthesized by grafting NC with aminopropylisobutyl polyhedral oligomeric silsesquioxane (amino-POSS) using isophorone diisocyanate (IPDI) as a crosslinking agent. The structure and elemental composition of the resulting products were confirmed by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (1H NMR and 29Si NMR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). It was found, based on the silicon mapping using energy dispersive X-ray spectroscopy (EDS), that amino-POSS was well dispersed in NC matrix. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) studies showed that hybrid amino-POSS-NC materials have higher thermal decomposition activation energy (Ea) compared to NC control sample. According to TGA results, the temperatures of 5 % weight loss (T5 %) and 50 % weight loss (T50 %) as well as the residual masses at 240 °C (CR240 °C), were increased as a result of NC modification with amino-POSS. As can be seen from the digital and scanning electron microscopy (SEM) images, the char layers of amino-POSS-NC hybrid materials after burning in air became more compact with increasing amino-POSS content. XPS studies have shown an increased content of the graphitized carbon in the char residues of the modified samples. The results of DSC, TGA, SEM and XPS studies have directly proved the enhancement of the thermal stability of amino-POSS-NC hybrid materials. In addition, tensile strengths and Young's moduli of amino-POSS-NC hybrid materials were increased gradually with the amino-POSS content in the uniaxial tensile tests. All these results show that the proposed modification of nitrocellulose improves the safety of manufacture and use of this material.

CO2 removal using membrane gas absorption with PVDF membrane incorporated with POSS and SAPO-34 zeolite

The mixed matrix membranes designed with enhanced affinity for CO2 by incorporating the gas selective fillers are studied in this work. Polyhedral oligomeric silsesquioxane (POSS) and SAPO-34 zeolite were selected to engineer the additional pathway for CO2 diffusion in polyvinylidenefluoride (PVDF) membrane in order to improve the CO2 removal via membrane gas absorption (MGA). The double-soft coagulation resulted in the neat PVDF membrane (M-0) with a mean pore size of 2.77±0.09μm and a water contact angle of 137.5°. M-S34 membrane with the hydrophilic SAPO-34 zeolite and M-AP membrane with aminopropylisobutyl POSS exhibited the smaller pore size and lower water contact angle than the neat membrane. Although the mean pore size of M-SP membrane with trisilanolisobutyl POSS (0.54±0.06μm) is small in comparison to M-0 membrane, it showed the similar water contact angle of 132.4 ° to M-0 membrane. The reduction of pore size could be related to the fast coagulation caused by different interactions between polymer, filler, solvents and non-solvents. Nevertheless, the blending of trisilanolisobutyl POSS into M-SP membrane still improved the CO2 absorption flux which is more than 2 times higher than the neat membrane. The functionality of SAPO-34 and aminopropylisobutyl POSS in the PVDF membranes was limited by the low pressure and membrane morphology, respectively.

Hybrid formation of graphene oxide–POSS and their effect on the dielectric properties of poly(aryl ether ketone) composites

Covalent functionalization of graphene oxide with aminopropylisobutyl polyhedral oligomeric silsesquioxane efficiently reduced the dielectric constant of the polymer matrix.

Synthesis and Characterization of Trifluoroethoxy Polyphosphazenes Containing Polyhedral Oligomeric Silsesquioxane (POSS) Side Groups

We report the macromolecular substitution synthesis of a series of soluble polyphosphazenes with different molar percentages of cosubstituted trifluoroethoxy and aminopropylisobutyl polyhedral oligomeric silsesquioxane R7Si8O12(CH2)3NH (R = isobutyl) (POSS-NH) cage side groups. The structure–property relationships of the novel polymers were examined using 1H, 31P NMR, GPC, FTIR, DSC, and TGA techniques, and properties such as contact angles, solubility, materials character, glass transitions, thermal stability, and molecular weight were measured. The average polymer chain length declined steadily from ∼3860 repeating units when only trifluoroethoxy side groups were present to 1354 repeat units when 25 mol % of the side groups were POSS, 603 units when 55 mol % were present, and only 36 units when 82 mol % of the side groups were POSS. At the same time the glass transition temperatures rose from −62 to +30.5 °C as the POSS content was increased. Unlike other bulky cosubstituents reported recently, the intr...

Effect of aminopropylisobutyl polyhedral oligomeric silsesquioxane functionalized graphene on the thermal conductivity and electrical insulation properties of epoxy composites

To obtain homogeneous dispersion and strong interfacial interaction in epoxy nanocomposites, an effective approach is proposed to prepare ApPOSS-graphene enhancement epoxy hybrids with high thermal conductivity and electrical insulating property.

POSS-tethered fluorinated diblock copolymers with linear- and star-shaped topologies: synthesis, self-assembled films and hydrophobic applications

Polyhedral oligomeric silsesquioxane (POSS) tethered fluorinated diblock copolymers are synthesized using octakis(dibromoethyl)POSS and aminopropylisobutyl POSS initiation of methylmethacrylate and dodecafluoroheptylmethacrylate.

POSS end-capped diblock copolymers: Synthesis, micelle self-assembly and properties

Polyhedral oligomeric silsesquioxane (POSS) end-capped diblock copolymers are synthesized using aminopropylisobutyl POSS (ap-POSS-Br) to initiate atom transfer radical polymerization (ATRP) of methylmethacrylate (MMA) and methacrylisobutyl POSS (MA-POSS). Their chemical structures are confirmed as ap-POSS–PMMA152.0-b-P(MA-POSS)4.3, 4.8, 10.0 with 19,840–24,770gmol−1 by 1H NMR and SEC. In tetrahydrofuran (THF) solution, the obtained diblock copolymers could self-assemble into 150–300nm core–shell micelles as ap-POSS/MA-POSS core and PMMA shell, or 164nm core–shell–crown micelles as P(MA-POSS) core, PMMA shell and ap-POSS crown when P(MA-POSS) content is increased. These micelles can produce typical films with lower surface roughness (0.816–1.690nm), lower water absorption and lower viscoelasticity, but higher hydrophobicity (112–126° water contact angle) and higher thermostability in glass transition temperature Tg>110°C and decompose temperature Td>380°C than pure POSS–PMMA film. In this study, the results strongly support the potential application of the POSS end-capped diblock copolymers as the coatings.