This communication reports the first example of precision polyolefin nanoalloys where an exotic immiscible polymer is nanometrically dispersed with stability in a polyolefin matrix in a highly controlled mode. Following the preparation of polypropylene/multiwalled carbon nanotubes nanocomposites (PP/MWCNTs) by in situ Ziegler‐Natta polymerization, the hydroxyl groups on the surfaces of individual MWCNTs are used to initiate ring‐opening polymerization of ε‐caprolactone, resulting in PP/poly(ε‐caprolactone) (PCL) alloy with PCL grafted on MWCNTs. Upon phase formation, the PP/MWCNTs‐g‐PCL alloys exhibit a unique PCL dispersion morphology, which is stable and solely governed by PCL molecular weight.
The synthesis of tetracene‐ and pentacene‐annulated norbornadienes, formed through the Diels–Alder reaction of a dehydroacene with cyclopentadiene is reported. Ring‐opening metathesis polymerization (ROMP) leads to polymers that are investigated with respect to their physical, optical, and electronic properties by gel permeation chromatography (GPC), UV–vis spectroscopy, and cyclic voltammetry. The pentacene‐containing polymer P1 is successfully integrated into an organic field‐effect transistor (OFET); the tetracene‐containing polymer P2 is integrated into an organic light‐emitting diode (OLED).
In this work, the synthesis of various halogenated thiophenol derivatives is presented. These thiophenols are used as monomers in light‐initiated SRN1‐type radical polymerization reactions. The method provides easy access to industrially relevant poly(paraphenylene sulfide) and poly(metaphenylene sulfide). The influence of the halide leaving group and of other substituents in the thiophenol monomer on the polymerization process is investigated.
Primary alcohol‐functionalized β‐diketones (bdks) are successfully synthesized via facile one‐step Claisen condensation between aromatic monoketones and ε‐caprolactone (ε‐CL). To demonstrate application potentials, these bdk alcohols are used to chelate with various Lewis acids, including Tb (III), Eu (III), and B (III). It is discovered that the resulting Tb (III) and Eu (III) diketonate complexes can serve as both catalysts and initiators for ring‐opening polymerization (ROP) under solvent‐free conditions, using lactide monomer as an example. The polylactides (PLAs) thus obtained exhibit luminescence properties characteristic of Tb (III) and Eu (III), respectively. On the other hand, boron‐chelated diketone can initiate ROP of lactide in the presence of Sn(oct)2, and affords a PLA material with dual‐emission, i.e., fluorescence and room temperature phosphorescence. The synthesis described here represents a shortcut for the preparation of bdk‐based macroligands and subsequent functional materials.
The coordination polymerization of silyl‐protected ω‐alkenols such as ω‐alken‐α‐oxytriisopropylsilanes 1 provides poly(ω‐alkenyl‐α‐oxytriisopropylsilalne)s with a highly isospecific microstructure ([mmmm] > 95%) when a combination of [OSSO]‐type bis(phenolato) dichloro zirconium(IV) complex 2 and dried methylaluminoxane is used as the precatalyst and activator, respectively. The resulting siloxy‐substituted polymers could be efficiently transformed into the corresponding functionalized polyolefins, which contained up to 90% acetyl groups and ≈7% hydroxy groups in the terminal side chains.
The synthesis of symmetric cyclo poly(ε‐caprolactone)–block–poly(l (d )‐lactide) (c(PCL–b–PL(D)LA)) by combining ring‐opening polymerization of ε‐caprolactone and lactides and subsequent click chemistry reaction of the linear precursors containing antagonist functionalities is presented. The two blocks can sequentially crystallize and self‐assemble into double crystalline spherulitic superstructures. The cyclic chain topology significantly affects both the nucleation and the crystallization of each constituent, as gathered from a comparison of the behavior of linear precursors and cyclic block copolymers. The stereochemistry of the PLA block does not have a significant effect on the nonisothermal crystallization of both linear and cyclo PCL‐b‐PDLA and PCL‐b‐PLLA copolymers.
The controlled synthesis of poly(oligo(2‐ethyl‐2‐oxazoline)methacrylate) (P(OEtOxMA)) polymers by Cu(0)‐mediated polymerization in water/methanol mixtures is reported. Utilizing an acetal protected aldehyde initiator for the polymerization, well‐defined polymers are synthesized (>99% conversion, Ð < 1.25) with subsequent postpolymerization deprotection resulting in α‐aldehyde end group containing comb polymers. These P(OEtOxMA) are subsequently site‐specifically conjugated, via reductive amination, to a dipeptide (NH2‐Gly‐Tyr‐COOH) as a model peptide, prior to conjugation to the functional peptide oxytocin. The resulting oxytocin conjugates are evaluated in comparison to poly(oligo(ethylene glycol) methyl ether methacrylate) combs synthesized in the same manner for potential effects on thermal stability in comparison to the native peptide.
High molecular weight cyclic poly(ε‐caprolactone)s (cPCLs) with variable ring size are synthesized via light‐induced ring closure of α,ω‐anthracene‐terminated PCL (An‐PCL‐An). The ring size of cPCL is tunable simply by adjusting the polymer concentration from 10 to 100 mg mL−1 in THF. The cycloaddition via the bimolecular cyclization of An‐PC‐An is well characterized by a variety of analyses such as 1H NMR and UV–vis spectroscopies, gel‐permeation chromatography, and differential scanning calorimetry. The reversible dimerization of An induced by heating enables the cyclic PCL to have a switchable “on–off” capability. This novel light‐induced ring‐closure technique can be one of the most powerful candidates for producing various well‐defined cyclic polymers in highly concentrated polymer solution.
To enhance the limited degradability of poly(ethylene glycol) (PEG), a straightforward method of synthesizing poly[(ethylene glycol)‐co‐(glycolic acid)] (P(EG‐co‐GA)) via a ruthenium‐catalyzed, post‐polymerization oxyfunctionalization of various PEGs is developed. Using this method, a set of copolymers with GA compositions of up to 8 mol% are prepared with minimal reduction in molecular weight (<10%) when compared to their commercially available starting materials. The P(EG‐co‐GA) copolymers are shown to undergo hydrolysis under mild conditions.
The synthesis of two 4,7,12,15‐tetrakisalkoxy‐substituted [2.2.2]‐paracyclophane‐1,9,17‐trienes and their polymerization employing ring opening metathesis polymerization (ROMP) using Ru‐carbenes (third‐generation Grubbs catalyst) is reported. Phenylene ethynylene trimers are reduced via a Grignard reagent, followed by an intramolecular McMurry cyclization to give the cyclophenes. The cyclophenes are polymerized into soluble poly(para‐phenylene vinylene)s (PPV), which are analyzed in solution by NMR, UV–vis, and fluorescence spectroscopy. They are spin coated into amorphous, fluorescent thin films, and investigated by optical spectroscopy and cyclic voltammetry.
To overcome drug delivery issues associated with its short half‐life in vivo, p‐coumaric acid (pCA), a naturally occurring bioactive, has been chemically incorporated into a poly(anhydride‐ester) backbone through solution polymerization. Nuclear magnetic resonance and Fourier transform infrared spectroscopies indicated that pCA was successfully incorporated without noticeable alterations in structural integrity. The polymer's weight‐average molecular weight and thermal properties were determined, exhibiting a molecular weight of over 26 000 Da and a glass transition temperature of 57 °C. In addition, in vitro hydrolytic release studies demonstrated pCA release over 30 d with maintained antioxidant activity, demonstrating the polymer's potential as a controlled release system.
Molecular bottle‐brush functionalized single‐walled carbon nanotubes (SWCNTs) with superior dispersibility in water are prepared by a one‐pot synthetic methodology. Elongating the main‐chain and side‐chain length of molecular bottle‐brushes can further increase SWCNT dispersibility. They show significant enhancement of SWCNT dispersibility up to four times higher than those of linear molecular functionalized SWCNTs.
Diarylbutadiyne derivatives are ideal monomers for providing the π‐electron‐conjugated system of polydiacetylenes (PDAs). The geometrical parameters for diacetylene topochemical polymerization are known. However, control of the molecules under these parameters is yet to be addressed. This work shows that by simply tailoring diarylbutadiyne with amide side‐chain substituents, the arrangement of the substituents and the resulting hydrogen bond framework allows formation of π‐electron‐conjugated PDA.
Furfuryl glycidyl ether (FGE) represents a highly versatile monomer for the preparation of reversibly cross‐linkable nanostructured materials via Diels–Alder reactions. Here, the use of FGE for the mid‐chain functionalization of a P2VP‐b‐PEO diblock copolymer is reported. The material features one furan moiety at the block junction, P2VP68‐FGE‐b‐PEO390, which can be subsequently addressed in Diels–Alder reactions using maleimide‐functionalized counterparts. The presence of the FGE moiety enables the introduction of dyes as model labels or the formation of hetero‐grafted brushes as shell on hybrid Au@Polymer nanoparticles. This renders P2VP68‐FGE‐b‐PEO390, a powerful tool for selective functionalization reactions, including the modification of surfaces.
The step‐wise solution self‐assembly of double crystalline organometallic poly(ferrocenyldimethylsilane)‐block‐poly(2‐iso‐propyl‐2‐oxazoline) (PFDMS‐b‐PiPrOx) diblock copolymers is demonstrated. Two block copolymers are obtained by copper‐catalyzed azide‐alkyne cycloaddition (CuAAC), featuring PFDMS/PiPrOx weight fractions of 46/54 (PFDMS30‐b‐PiPrOx75) and 30/70 (PFDMS30‐b‐PiPrOx155). Nonsolvent induced crystallization of PFDMS in acetone leads in both cases to cylindrical micelles with a PFDMS core. Afterward, the structures are transferred into water for sequential temperature‐induced crystallization of the PiPrOx corona, leading to hierarchical double crystalline superstructures, which are investigated using scanning electron microscopy, wide angle X‐ray scattering, and differential scanning calorimetry.
Novel amphiphilic polypeptoid‐polyester diblock copolymers based on poly(sarcosine) (PSar) and poly(ε‐caprolactone) (PCL) are synthesized by a one‐pot glovebox‐free approach. In this method, sarcosine N‐carboxy anhydride (Sar‐NCA) is firstly polymerized in the presence of benzylamine under N2 flow, then the resulting poly(sarcosine) is used in situ as the macroinitiator for the ring‐opening polymerization (ROP) of ε‐caprolactone using tin(II) octanoate as a catalyst. The degree of polymerization of each block is controlled by various feed ratios of monomer/initiator. The diblock copolymers with controlled molecular weight and narrow molecular weight distributions (ĐM < 1.2) are characterized by 1H NMR, 13C NMR, and size‐exclusion chromatography. The self‐assembly behavior of PSar‐b‐PCL in water is investigated by dynamic light scattering (DLS) and transmission electron microscopy. DLS results reveal that the diblock copolymers associate into nanoparticles with average hydrodynamic diameters (DH) around 100 nm in water, which may be used as drug delivery carriers.
In this study, the group transfer polymerization (GTP) of the functional monomer 3‐(trimethoxysilyl)propyl methacrylate (TMSPMA) is reported to produce polymers of different architectures and topologies. TMSPMA is successfully polymerized and copolymerized with GTP to produce well‐defined (co)polymers that can be used to fabricate functional hybrid materials like hydrogels and films.
A novel one‐component type II polymeric photoinitiator, poly(vinyl alcohol)–thioxanthone (PVA–TX), is synthesized by a simple acetalization process and characterized. PVA–TX enables photopolymerization of methyl methacrylate and acrylamide in both organic and aqueous media. Photopolymerization proceeds even in the absence of a co‐initiator since PVA–TX possesses both chromophoric and hydrogen donating sites in the structure.
Cyclic multiblock polymers with high‐order blocks are synthesized via the combination of single‐electron transfer living radical polymerization (SET‐LRP) and copper‐catalyzed azide‐alkyne cycloaddition (CuAAC). The linear α,ω‐telechelic multiblock copolymer is prepared via SET‐LRP by sequential addition of different monomers. The SET‐LRP approach allows well control of the block length and sequence as A‐B‐C‐D‐E, etc. The CuAAC is then performed to intramolecularly couple the azide and alkyne end groups of the linear copolymer and produce the corresponding cyclic copolymer. The block sequence and the cyclic topology of the resultant cyclic copolymer are confirmed by the characterization of 1H nuclear magnetic resonance spectroscopy, gel permeation chromatography, Fourier transform infrared spectroscopy, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry.
The performance of polymer field‐effect transistors (PFETs) based on short rigid rod semiconducting poly(2,5‐didodecyloxy‐p‐phenyleneethynylene) (D‐OPPE) is highlighted. The controlled heating and cooling of thin films of D‐OPPE allows for a recrystallization from the melt, boosting the performance of D‐OPPE‐based transistors. The improved film properties induced by controlled annealing lead to a hole field‐effect mobility around 0.014 cm2 V−1 s−1, an on/off ratio of 106, a sub‐threshold swing of 3 V dec−1 and a threshold voltage of −35 V, employing a poly(methyl methacrylate) (PMMA) gate dielectric. Thus, PFETs out of D‐OPPE compete now with spin‐coated, polycrystalline poly(3‐hexylthiophene)‐based PFETs.
