Janus POSS Based on Mixed [2:6] Octakis‐Adduct Regioisomers

A series of regioisomeric Janus‐type polyhedral oligomeric silsesquioxanes (POSS) with multiple, mixed surface functional groups has been successfully synthesized based on the cubic T₈‐POSS framework in two consecutive thiol–ene reactions. The first thiol–ene addition of β‐mercaptoethanol leads to a statistical mixture of multi‐adducts where the regioisomers of bis‐adducts (ortho, meta, and para isomers) can be isolated at synthetically useful quantities by flash column chromatography. Then, the second thiol–ene reaction readily installs a variety of functional groups onto the remaining vinyl groups of each regioisomer, providing an easy access to precisely defined, hetero‐bifunctional Janus POSS nano‐building blocks. The configurations and structures of the products have been unambiguously proven by using ¹H, ¹³C, and ²⁹Si NMR spectroscopy as well as MALDI‐TOF mass spectrometry.     

POSS‐nylon 6 nanocomposites: Influence of POSS structure on surface and bulk properties

Hybrid organic/inorganic nanocomposites based on polyhedral oligomeric silsesquioxane (POSS) nanostructured chemicals and nylon 6 were prepared via melt mixing. Two structurally and chemically different POSS molecules, a closed cage, nonpolar octaisobutyl POSS (Oib‐POSS) and an open cage, polar trisilanolphenyl POSS (Tsp‐POSS) with differing predicted solubility parameters were evaluated in the nylon matrix. Surface analysis, including quasi‐static and dynamic nanoindentation and nanotribological techniques, revealed exceptional improvements in modulus and hardness along with significant reductions in friction. Additionally, surface wetting characteristics of the nylon were reversed, with POSS incorporation yielding low surface energy, highly hydrophobic surfaces. AFM, TEM/EDAX, spectroscopic techniques and thermomechanical analysis were used to evaluate nanoscale dispersion and bulk properties of the composites. Both POSS molecules exhibit preferential surface segregation behavior in the nylon matrix. Tsp‐POSS, with its higher predicted solubility in nylon, exhibited enhanced dispersion and tribomechanical properties at both nano and bulk scale. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1088–1102, 2009     

Dramatic Shape Modulation of Surfactant/Diacetylene Microstructures at the Air–Water Interface

Langmuir monolayers constitute a powerful platform for self‐assembly and organization of amhiphilic molecules. Controlling the structural features of condensed domains formed within Langmuir monolayers, however, is a challenging task. The formation of remarkably diverse condensed microstructures is demonstrated in binary monolayers comprising of a surfactant (octadecylmelamine) and a diacetylene monomer. The mole ratio between the two constituents and composition of the aqueous subphases (specifically pH and which dissolved metal ions are present) dramatically modulated the shapes and dimensions of microstructures formed at the air–water interface. The self‐assembled microstructures could be transferred from the water surface onto solid substrates, and subsequently further served as templates for gold coating, yielding electrically conductive microwires.     

Synthesis and langmuir‐blodgett (LB) film properties of functional α,ω‐diamine amphiphilic materials

We have investigated the synthesis and ultrathin film forming properties of α,ω‐diamine derivatives. The amphiphiles were synthesized as precursors to the formation of ionene polymers. Two materials were investigated: oligothiophene and azobenzene functional groups. These type of materials are of great interest for the preparation of ultrathin film layers with applications for photochemical regulation of liquid crystal (LC) orientation, optical storage media, and electroluminescent displays. Azobenzene and its derivatives are well known photochemical systems exhibiting the reversible cis‐trans photoisomerization. Conjugated oligothiophene derivatives, exhibit interesting optical and electronic properties for applications such as light emitting diodes (LED)s, Schottky diodes, and thin film field‐effect transistors (TFT). The two amphiphiles behaved very differently as Langmuir monolayers and LB films. Dye aggregation was observed with the azobenzene derivatives compared with the oligothiophenes.     

Preparation and characterization of redox cellulose Langmuir–Blodgett films containing a ferrocene derivative

The 3‐ferrocenoylpropanoyl group, one of the redox species, was introduced at C‐2 and/or C‐3 positions of 6‐O‐(4‐stearyloxytrityl)cellulose. The spreading behavior of the cellulose derivatives on the water surface and the properties of Langmuir–Blodgett (LB) films were investigated. The surface pressure–area isotherm of the cellulose monolayer was changed by the subphase temperature. Uniform monolayers of 6‐O‐(4‐stearyloxytrityl)cellulose 3‐ferrocene propionate (STCFc) could be deposited successively onto several substrates by the horizontal lifting method at 10 mN m^?1, and this produced X‐type LB films. The successive uniform depositions of STCFc were confirmed by ultraviolet–visible absorption spectra. X‐ray diffraction measurements indicated that the thickness of the STCFc molecules in the LB films was 1.99 nm. Fourier transform infrared spectroscopy measurements supported the idea that hydrocarbon chains in the LB films were highly ordered (trans‐zigzag) and oriented considerably perpendicular to the surface of the substrate. Moreover, the C?O group of the ferrocenoyl groups was perpendicular to the surface of the substrate, and the ferrocene group was occupied in the water phase. Cyclic voltammograms for the STCFc monolayer on a gold electrode exhibited surface waves. The interfacial electron‐transfer process between the redox site incorporated into the cellulose LB monolayer and the electrode surface was fast enough at a scanning rate lower than 100 mV s^?1. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5023–5031, 2005     

Synthesis and properties of low‐dielectric‐constant polyimides with introduced reactive fluorine polyhedral oligomeric silsesquioxanes

A high‐performance, low‐dielectric‐constant polyimide (PI) nanocomposite from poly(amic acid) (PAA) cured with a reactive fluorine polyhedral oligomeric silsesquioxane (POSS) isomer was successfully synthesized. The features of this reactive fluorine POSS isomer [octakis(dimethylsiloxyhexafluoropropylglycidyl ether)silsesquioxane (OFG)] provided two important approaches (containing fluorine or being porous in the polymer matrix) of reducing the dielectric constant of PI. This reactive POSS isomer had an average of four epoxy groups and four fluorine groups on the POSS cage, and the epoxy groups could be cured with PAA to form a network framework of a PI/POSS nanocomposite. The PI/OFG nanocomposite had a high crosslinking density, high porosity (24.3%), high hydrophobicity, and low polarizability. These properties enhanced the thermal (glass‐transition temperature ～ 362 °C) and dielectric (dielectric constant ～2.30) properties of PI more than other POSS derivatives introduced into the PI backbone. A large number of small POSS particles (<10 nm) were embedded inside the PI matrix when the OFG content was low, whereas interconnected POSS aggregation domains were observed when the OFG content was high. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5391–5402, 2006     

Synthesis,Characterization, and Thermal Behavior of Carboranyl–Styrene Decorated Octasilsesquioxanes: Influence of the Carborane Clusters on Photoluminescence

Novel polyhedral oligomeric silsesquioxanes (POSS) or octasilsesquioxanes with carboranyl–styrene fragments attached to each corner are described. These compounds have been synthesized by olefin‐metathesis reactions between octavinylsilsesquioxane and carboranyl–styrene compounds that possess different substituents (Ph, Me, or H). In all cases, these reactions, which were catalyzed by the Grubbs catalyst, are highly regioselective and yield exclusively the E isomers. The existence of the carborane cage in the POSS structure induces a remarkable thermal stability in these compounds. After combustion at 1000 °C, these carboranyl–POSS compounds exhibit a mass loss lower than 10 %. The UV/Vis absorption data of these carboranyl–POSS compounds shows a slight bathochromic shift with respect to the carboranyl–styrene monomers, with an absorption maximum around 262 nm. Nevertheless, important differences in the emission spectra of the carboranyl–POSS compounds with regard to their carboranyl–styrene precursors are observed; the phenyl‐o‐carborane‐containing POSS compound exhibits the highest fluorescence intensity (Φ_F=44 %), whereas for the POSS compound bearing the methyl substituent, and for the unsubstituted o‐carborane clusters, the fluorescence intensity is much lower (Φ_F=9 and 2 %, respectively). This is precisely the reverse of what occurs with the monomers, in which the unsubstituted o‐carboranyl–styrene compound exhibits the highest Φ_F, and a quenching of the fluorescence is observed in the phenyl‐o‐carboranyl–styrene compound. In addition, a large red shift of around 100 nm is observed for the POSS compounds with respect to their precursors. These experimental results can only be accounted for by the spatial ordering induced by the POSS core that eases interactions, which otherwise would not occur. These results have been confirmed by time‐dependent density functional theory (TDDFT) calculations that exclude a photoinduced electron transfer (PET) process in the POSS compounds.     

Attachment of Amine‐ and Maleimide‐Containing Ferrocene Derivatives onto Self‐Assembled Alkanethiol and Alkanedithiol Monolayers: Voltammetric Evaluation of Cross‐Linking Efficiencies and Surface Coverage of Electroactive Groups

Ferrocene derivatives containing primary amines and maleimide groups were attached covalently onto N‐hydrosuccinimidyl (NHS)‐terminated alkanethiol self‐assembled monolayers (SAMs) and SAMs of alkanedithiol. The surface coverage and efficiencies of the two cross‐linking reactions were evaluated with cyclic voltammetry. All the ferrocene derivatives attached onto the alkanethiol or alkanedithiol SAMs exhibit reversible redox waves. The surface coverage of the aminated ferrocene groups was compared to that of N‐hydrosuccinimidyl (NHS)‐terminated alkanethiol SAM. The covalent attachment of β‐ferrocenylethylamine onto a 11,11′‐dithio‐bis(succinimidylundecanoate) SAM yielded an efficiency as high as 63.1%. The cross‐linking efficiency of this reaction was found to increase with the nucleophilicity of the amino groups. SAMs of longer alkyl chains favor the attachment of a greater number of ferrocene derivatives. As for the Michael‐type electrophilic addition between the sulfhydryl groups of the alkanedithiol SAMs and the ferrocenyl maleimide, the cross‐linking efficiencies were found to range from 6.5% to 25.7%, depending on the alkanedithiol chain length. The difference in the efficiencies between the two types of cross‐linking reactions might be partially attributable to the steric hindrance imposed by the SAMs and the relative sizes of the functional groups.     

Synthesis,morphology, and properties of hydroxyl terminated‐POSS/polyimide low‐k nanocomposite films

Polyhedral oligomeric silsequioxane (POSS), having eight hydroxyl groups for the preparation of nanocomposites with polyimide (PI) was synthesized by the direct hydrosilylation of allyl alcohol with octasilsesquioxane (Q₈M₈^H) with platinum divinyltetramethyl disiloxane Pt(dvs) as a catalyst. The structure of allyl alcohol terminated‐POSS (POSS‐OH) was confirmed by FTIR, NMR, and XRD. A high performance, low‐k PI nanocomposite from pyromellitic dianhydride (PMDA)‐4,4'‐oxydianiline (ODA) polyamic acid cured with POSS‐OH was also successfully synthesized. The incorporation of POSS‐OH into PI matrix reduced dielectric constant of PI without loosing mechanical properties. Furthermore, the effects of POSS‐OH on the morphology and properties of the PI/POSS‐OH nanocomposites were investigated using UV–vis, FTIR, XRD, SEM, AFM, transmission electron microscope (TEM), TGA, and contact angle. The homogeneous dispersion of POSS particles was confirmed by SEM, AFM, and TEM. The nanoindentation showed that the modulus increased upon increasing the concentration of POSS‐OH in PI, whereas the hardness did not increase very much with respect to loading of POSS, due to soft‐interphase around POSS molecules in the resulting nanocomposites. Overall results demonstrated the nanometer‐level integration of the polymer and POSS‐OH. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5887–5896, 2008     

Characterisation of N‐(Octadecyl)‐1,8‐naphthalimide Monolayer Compression Using Molecular Dynamics and Experimental Approaches

The development of luminescent surfaces is an active area of supramolecular chemistry, particularly for the development of new sensing platforms. One particularly useful surface deposition method is the Langmuir–Blodgett technique where organic amphiphilic fluorophores (e.g. 1,8‐naphthalimides) can form ordered monolayers at an air–water interface before being deposited onto solid supports. The ability to simulate monolayer formation and consequently develop predictability over film formation would allow for significant advances in the luminescent materials field where synthesis might be directed by simulation data. Here, we compare pressure‐area isotherms of N‐(octadecyl)‐1,8‐naphthalimide determined experimentally, using the Langmuir–Blodgett technique, and computationally, using three different simulation techniques. We find that all three simulation techniques are able to describe the liquid‐condensed/liquid‐expanded region of the isotherm, and that the isotherms are highly similar in this region, although the NγT ensemble performs best. Experimental isotherms showed film formation properties that align with the simulation data, suggesting that simulations are a viable means to direct synthesis. Investigation of the underlying structural details disclosed by the simulations reveals the compression‐induced ordering at atomic‐level detail, which will allow prediction of how functionalisation of the naphthalimides will alter the monolayer compression and mounting process.     

Physically cross‐linked networks of POSS‐capped poly(acrylate amide)s: Synthesis,morphologies, and shape memory behavior

In this work, we synthesized a novel organic–inorganic semitelechelic polymer from polyhedral oligomeric silsesquioxane (POSS) and poly(acrylate amide) (PAA) via reversible addition‐fragmentation chain transfer (RAFT) polymerization. The organic–inorganic semitelechelic polymers have been characterized by means of nuclear magnetic resonance spectroscopy, thermal gravimetric analysis, and dynamic mechanical thermal analysis. It was found that capping POSS groups to the single ends of PAA chains caused a series of significant changes in the morphologies and thermomechanical properties of the polymer. The organic–inorganic semitelechelics were microphase‐separated; the POSS microdomains were formed via the POSS–POSS interactions. In a selective solvent (e.g., methanol), the organic–inorganic semitelechelics can be self‐assembled into the micelle‐like nanoobjects. Compared to plain PAA, the POSS‐capped PAAs significantly displayed improved surface hydrophobicity as evidenced by the measurements of static contact angles and surface atomic force microscopy. More importantly, the organic–inorganic semitelechelics displayed typical shape memory properties, which was in marked contrast to plain PAA. The shape memory behavior is attributable to the formation of the physically cross‐linked networks from the combination of the POSS–POSS interactions with the intermolecular hydrogen‐bonding interactions in the organic–inorganic semitelechelics. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 587–600     

Amphiphilic Fullerene‐Cholesterol Derivatives: Synthesis and Preparation of Langmuir and Langmuir‐Blodgett Films

Amphiphilic fullerene bis‐adducts 11 and 14 containing two and four cholesterol moieties, respectively, were prepared starting from the corresponding bis‐malonate derivatives. In a systematic study, their spreading behavior at the air‐water interface was compared to that of bis‐adduct 6 with no polar head‐group. Compared to 6 , for which some three‐dimensional aggregation occurs, the polar head‐group in 11 and 14 is responsible for an attractive interaction with the aqueous subphase, forcing the molecules towards the water surface into a two‐dimensional arrangement. Even if homogeneous Langmuir films were obtained with both 11 and 14 , only the films of 14 show a reversible compression/expansion behavior. This suggests that, by increasing the number of cholesterol subunits, the encapsulation of the C‐sphere in its addend is more efficient, thus preventing fullerene‐fullerene interactions and aggregation phenomena. The Langmuir films of 11 and 14 were also efficiently transferred onto hydrophilic quartz slides, yielding Langmuir‐Blodgett films.     

Preparation,characterization, and properties of novel biodegradable aliphatic–aromatic copolyester nanohybrids with polyhedral oligomeric silsesquioxanes moieties

Biodegradable aliphatic–aromatic copolyester nanohybrids, with polyhedral oligomeric silsesquioxane (POSS) moieties tethered between poly(lactic acid) (PLA) and poly(butylene terephthalate) segments, is designed and prepared. First, (bis(2‐hydroxyethyl) dipropionate POSS, BH‐POSS) is synthesized under mild conditions, then in situ polycondensation is carried out in the presence of terephthalic acid, PLA oligomer, 1,4‐butanediol, and BH‐POSS. 1 H‐NMR and Fourier transfer infrared spectroscopy confirm that Michael addition reaction of amino‐POSS and hydroxyethyl acrylate takes place efficiently and forms BH‐POSS in high yield at room temperature. Owing to similar functional groups, BH‐POSS could be easily incorporated into the macromolecular chains and obtain final copolyester nanohybrids. Moreover, X‐ray diffractometry and transmission electron microscopy observations demonstrate that POSS moieties occur self‐assembly behaviors and form nanoaggregates with the diameter of 50–100 nm. The thermal stability and mechanical properties of the copolyester nanohybrids containing BH‐POSS are substantially improved. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Preparation of carboxyl‐functionalized polyhedral oligomeric silsesquioxane by a structural transformation reaction from soluble rod‐like polysilsesquioxane

Carboxyl‐functionalized polyhedral oligomeric silsesquioxane (SQ; POSS‐COOH ) was successfully prepared by a structural transformation reaction, that is, a process of heating and concentrating soluble carboxyl‐functionalized rod‐like polySQ (PolySQ ‐COOH ) using the aqueous superacid trifluoromethanesulfonic acid (HOTf) as the catalyst and solvent. The obtained POSS‐COOH was a mixture of a cage‐like decamer (T₁₀‐POSS), which was the main product, and an octamer (T₈‐POSS) and a dodecamer (T₁₂‐POSS), which were the minor products. The product obtained by heating and concentrating PolySQ‐COOH using aqueous hydrochloric acid (HCl) as the catalyst and solvent was soluble polySQ rather than POSS. For comparison, heating and concentrating POSS‐COOH in aqueous HOTf and HCl were performed, which yielded POSS‐COOH and PolySQ‐COOH , respectively. Based on these results, the process of heating and concentrating each starting material ( PolySQ‐COOH and POSS‐COOH ) in aqueous HOTf afforded POSS‐COOH , and a similar process in aqueous HCl yielded PolySQ‐COOH . © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 2511–2518     

Towards the Fabrication of the Top‐Contact Electrode in Molecular Junctions by Photoreduction of a Metal Precursor

Langmuir films of 4‐{[4‐({4‐[(trimethylsilyl)ethynyl]phenyl}ethynyl)phenyl]ethynyl} benzenaminium chloride ([ 1 H ]Cl) undergo anion metathesis when assembled on an aqueous auric acid (HAuCl₄) subphase. Subsequent transfer to solid supports gives well‐formed Langmuir–Blodgett (LB) monolayers of [ 1 H ]AuCl₄ in which the trimethylsilyl group serves as the surface contacting group. Photoreduction of the aurate on these monolayers leads to the formation of metallic gold nanoislands, which were distributed over the surface of the film. Electrical properties of these nascent devices were determined by recording current–voltage (I–V) curves with conductive atomic force microscopy (c‐AFM) using the PeakForce tunneling AFM (PF‐TUNA) mode. This gives consistent sigmoidal I–V curves that are indicative of well‐behaved junctions free of metallic filaments and short circuits. The photoreduction of a metal precursor incorporated onto monomolecular films is therefore proposed as an effective method for the fabrication of molecular junctions.     

Fast fabrication of a hybrid monolithic column containing cyclic and aliphatic hydrophobic ligands via photo‐initiated thiol‐ene polymerization

Three monomers, octakis (3‐mercaptopropyl) octasilsesquioxane, 1,2,4‐trivinylcyclohexane and isophytol were employed to synthesize a novel monolithic stationary phase via photo‐initiated thiol‐ene click polymerization for reversed‐phase liquid chromatography. Several factors such as porogenic system, reaction time and the molar ratio of functional groups were investigated in detail. The resulting poly(POSS‐co‐TVCH‐co‐isophytol) monolithic column exhibited suitable permeability for fast separation and outstanding thermal stability. Five alkylbenzenes were employed to evaluate the ability of chromatographic separation of the resulting monolithic columns at different flow rates, and showed the highest column efficiencies of 90,200–93,100 N/m (corresponding to 10.4–10.6 μm of plate height) at a velocity of 0.41 mm/s. The baseline separations of five anilines and eight phenols further proved the applicability of poly(POSS‐co‐TVCH‐co‐isophytol) monolithic column in the separation of small molecules.     

Crystallization behavior and morphological development of isotactic polypropylene blended with nanostructured polyhedral oligomeric silsesquioxane molecules

The thermal properties and morphological development of isothermally crystallized isotactic polypropylene (iPP) blended with nanostructured polyhedral oligomeric silsesquioxane (POSS) molecules at very small loading of POSS were studied with differential scanning calorimeter (DSC), thermal gravimetric analysis, dynamic mechanical analysis, polarized optical microscopy (POM), and wide‐angle X‐ray diffraction (WAXD). The result of DSC indicated that the crystallization rate of iPP increases with the increase in POSS contents during crystallization; moreover, the melting temperature of iPP/POSS nanocomposites slightly decreases, while the heat of fusion increases with the addition of POSS molecules at melting and remelting traces. The storage modulus and thermal stability, respectively, remarkably decrease, while the glass transition temperature of isothermally crystallized iPP/POSS nanocomposites increases slightly with the increase in POSS contents. The morphologies results of WAXD and POM show that the POSS molecules form about 35 nm sized nanocrystals and aggregate to form thread‐like and network structure morphologies, respectively, in the molten state even when the POSS content is very small. These results, therefore, suggest that the interaction force between the POSS molecules should be larger than the force between POSS molecules and iPP matrix; however, those interactions depend on the chain length of functionalized substituents on the POSS cage. Therefore, the POSS molecules aggregate forming nanocrystals and act as an effective nucleating agent for iPP and influence the thermal properties of iPP/POSS nanocomposites due to the shorter chain length of functionalized substituents, methyl, on the POSS cage. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2122–2134, 2006     

Formation of Langmuir layers and surface modification using new upper-rim fully tethered bipyridinyl or bithiazolyl cyclodextrins and their fluorescent metal complexes

Seven new amphiphilic cyclodextrins bearing bipyridyl or bithiazolyl moieties at the narrow rim and free hydroxyl or methoxyl groups at the wide rim of the cyclooctaamylose crown were synthesized using a one step "phosphine imide" approach. These ligands form metal complexes that have fluorescence properties with potentials for optical applications. Here, the cyclodextrin derivatives were used as probes for evaluating the role of different moieties in the self-assembly process, providing crucial information in creating functional devices. The behavior of these molecules and of complexes with EuIII in some cases was studied in Langmuir films using surface pressure (pi) and surface potential (deltaV) measurements performed as a function of film compression (compression isotherms). For chosen cyclodextrins, Brewster angle microscopy (BAM) in monolayers was performed. Films formed with derivatives 1, 3, 7, and 2compl were transferred on mica using the Langmuir-Blodgett technique. The properties of the films deposited on mica were analyzed with fluorimetry and, in the case of derivative 7, using fringe of equal chromatic order technique (FECO). The monolayer structure and the fluorescence properties of the Langmuir-Blodgett films indicate that the derivatives studied can be used for preparing cyclodextrin-based optical devices.     

POSS end‐linked peptide‐functionalized poly(ɛ‐caprolactone)s and their inclusion complexes with α‐cyclodextrin

In this report, we have synthesized organic/inorganic hybrid peptide–poly(?‐caprolactone) (PCL) conjugates via ring opening polymerization (ROP) of ?‐caprolactone (CL) in the presence of two sequence defined peptide initiators, namely POSS‐Leu‐Aib‐Leu‐NH₂ (POSS: polyhedral oligomeric silsesquioxane; Leu: Leucine; Aib: α‐aminoisobutyric acid) and OMe‐Leu‐Aib‐Leu‐NH₂. Covalent attachment of peptide segments with the PCLs were examined by ¹H and ²⁹Si NMR spectroscopy, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) and FTIR spectroscopy. Supramolecular inclusion complexations of synthesized peptide‐PCL conjugates with α‐cyclodextrin (α‐CyD) were studied to understand the effect of POSS/OMe‐peptide moieties at the PCL chain ends. Inclusion complexation of peptide‐PCL conjugates with α‐CyD produced linear polypseudorotaxane, confirmed by ¹H NMR, FTIR, powder X‐ray diffraction (PXRD), polarized optical microscopy (POM) and differential scanning calorimetry (DSC). Extent of α‐CyD threading onto the hybrid peptide‐PCL conjugated polymers is less than that of α‐CyD threaded onto the linear PCL. Thus, PCL chains were not fully covered by the host α‐CyD molecules due to the bulky POSS/OMe‐peptide moieties connected with the one edge of the PCL chains. PXRD experiment reveals channel like structures by the synthesized inclusion complexes (ICs). Spherulitic morphologies of POSS/OMe‐peptide‐PCL conjugates were fully destroyed after inclusion complexation with α‐CyD and tiny nanoobjects were produced. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3643–3651.     

Supramolecular inclusion complexation of polyhedral oligomeric silsesquioxane capped poly(ε‐caprolactone) with α‐cyclodextrin

Supramolecular inclusion complexes (ICs) involving polyhedral oligomeric silsesquioxane (POSS) capped poly(?‐caprolactone) (PCL) and α‐cyclodextrin (α‐CD) were investigated. POSS‐terminated PCLs with various molecular weights were prepared via the ring‐opening polymerization of ?‐caprolactone (CL) with 3‐hydroxypropylheptaphenyl POSS as an initiator. Because of the presence of the bulky silsesquioxane terminal group, the inclusion complexation between α‐CD and the POSS‐capped PCL was carried out only with a single end of a PCL chain threading inside the cavity of α‐CD, which allowed the evaluation of the effect of the POSS terminal groups on the efficiency of the inclusion complexation. The X‐ray diffraction results indicated that the organic–inorganic ICs had a channel‐type crystalline structure. The stoichiometry of the organic–inorganic ICs was quite dependent on the molecular weights of the POSS‐capped PCLs. With moderate molecular weights of the POSS‐capped PCLs (e.g., M_n =3860 or 9880), the stoichiometry was 1:1 mol/mol (CL unit/α‐CD), which was close to the literature value based on the inclusion complexation of α‐CD with normal linear PCL chains with comparable molecular weights. When the PCL chains were shorter (e.g., for the POSS‐capped PCL of M_n = 1720 or 2490), the efficiency of the inclusion complexation decreased. The decreased efficiency of the inclusion complexation could be attributed to the lower mobility of the bulky POSS group, which restricted the motion of the PCL chain attached to the silsesquioxane cage. This effect was pronounced with the decreasing length of the PCL chains. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1247–1259, 2007