AB′ type monomers containing a thiolactone unit and vinyl ether moiety have been prepared with high yields. Aminolysis of the thiolactone moiety generates the corresponding thiol in situ, and upon UV‐irradiation, radical polyaddition occurs in the same medium, yielding linear poly(amide‐urethane)s with different side chain residues and (Poly(Ethylene Oxide)) PEO‐like backbone. Moreover, these unique polymers feature lower critical solution temperature behavior in water. Systematic modification of the responsive polymers reveals the influence of the variation of the side chains and the backbone structure on the corresponding solubility properties. In selected cases, multiresponsive polymers have been developed, which also respond to pH and metal concentration.
This work deals with the in‐depth investigation of thiol‐yne based network formation and its effect on thermomechanical properties and impact strength. The results show that the bifunctional alkyne monomer di(but‐1‐yne‐4‐yl)carbonate ( DBC ) provides significantly lower cytotoxicity than the comparable acrylate, 1,4‐butanediol diacrylate ( BDA ). Real‐time near infrared photorheology measurements reveal that gel formation is shifted to higher conversions for DBC /thiol resins leading to lower shrinkage stress and higher overall monomer conversion than BDA . Glass transition temperature (Tg), shrinkage stress, as well as network density determined by double quantum solid state NMR, increase proportionally with the thiol functionality. Most importantly, highly cross‐linked DBC /dipentaerythritol hexa(3‐mercaptopropionate) networks (Tg ≈ 61 °C) provide a 5.3 times higher impact strength than BDA , which is explained by the unique network homogeneity of thiol‐yne photopolymers.
An alkyne‐functionalized ruthenium(II) bis‐terpyridine complex is directly copolymerized with phenylacetylene by alkyne polymerization. The polymer is characterized by size‐exclusion chromatography (SEC), 1H NMR spectroscopy, cyclic voltammetry (CV) measurements, and thermal analysis. The photophysical properties of the polymer are studied by UV–vis absorption spectroscopy. In addition, spectro‐electrochemical measurements are carried out. Time‐resolved luminescence lifetime decay curves show an enhanced lifetime of the metal complex attached to the conjugated polymer backbone compared with the Ru(tpy)22+ model complex.
A convenient synthesis of sustainable polyamides, which contain side groups and stereocenters, starting from the biobased small terpene β‐pinene is reported. The polyamides, which are obtained via the pinene‐based lactam via ring‐opening polymerization, show excellent thermal properties, rendering this approach very interesting for the utilization of novel biobased and structurally significant high‐performance polymers and materials. Polymer masses and yields are shown to be dependent on different parameters, and the stereoinformation of the lactam monomer can thus be transferred into the polymer chain. In addition, another lactam side product can also be transformed to polyamides.
A novel strategy for the incorporation of carbon dioxide into polymers is introduced. For this purpose, the Ugi five‐component condensation (Ugi‐5CC) of an alcohol, CO2, an amine, an aldehyde, and an isocyanide is used to obtain step‐growth monomers. Polymerization via thiol‐ene reaction or polycondensation with diphenyl carbonate gives diversely substituted polyurethanes or alternating polyurethane‐polycarbonates, respectively. Furthermore, the application of 1,12‐diaminododecane and 1,6‐diisocyanohexane as bifunctional components in the Ugi‐5CC directly results in the corresponding polyamide bearing methyl carbamate side chains ( = 19 850 g mol−1). The latter polymer is further converted into the corresponding polyhydantoin in a highly straightforward fashion.
Hybrid cylindrical micelles loaded with nanoparticles are fabricated via extrusion of spherical micelles in solution phase through small long cylindrical pores. Small gold nanoparticles (AuNPs) are pre‐coated with thiol‐terminated polystyrene and then further encapsulated in the core part of block copolymer spherical micelles by a precipitation method. By varying the starting mass ratio of AuNPs and the diblock copolymers polystyrene‐b‐polyisoprene (PS‐b‐PI) during the encapsulation, the AuNPs loading density along the cylindrical micelles can be controlled. The mechanism for this sphere‐to‐cylinder transition induced by extruding hybrid spherical micelles through small cylindrical nanopores is discussed. These findings provide a novel way to manufacture high‐quality and functional polymeric nanowires, which may open the door to new applications such as in plasmonic waveguides.
The synthesis, tunable thermoresponsive properties, and self‐assembly of dual redox and thermoresponsive double hydrophilic block copolymers having pendant disulfide linkages (DHBCss) are reported. Well‐defined DHBCss composed of a hydrophilic poly(ethylene oxide) block and a dual thermo‐ and reduction‐responsive random copolymer block containing pendant disulfide linkages are synthesized by atom transfer radical polymerization. Their lower critical solution temperature (LCST) transitions are adjusted through modulating pendant hydrophobic–hydrophilic balance with disulfide–thiol–sulfide chemistry. Further, these DHBCss derivatives are converted to disulfide‐crosslinked nanogels at temperatures above LCST through temperature‐driven self‐assembly and in situ disulfide crosslinking. They exhibit enhanced colloidal stability and further reduction‐responsive degradability, thus demonstrating versatility of dual thermo‐ and reduction‐responsive smart materials.
The synthesis of thiol‐functionalized long‐chain highly branched polymers (LCHBPs) has been accomplished in combination of ring‐opening metathesis polymerization (ROMP) and thiol‐Michael addition click reaction. A monotelechelic polymer with a terminal acrylate and many pendent thiol groups is first prepared through adding an internal cis‐olefin terminating agent to the reaction mixture immediately after the completion of the living ROMP, and then utilized as an ABn‐type macromonomer in subsequent thiol‐ene reaction between acrylate and thiol, yielding LCHBPs as the reaction time prolonged. Au nanoparticles are then covalently conjugated onto the surface of thiol‐functionalized LCHBP to fabricate novel hybrid nanostructures, which is shown as one interesting application of such functionalized metathesis polymers. This facile approach can be extended toward the fabrication of novel nanomaterials with sophisticated structures and tunable multifunctionalities.
The chemical control of cell division has attracted much attention in the areas of single cell‐based biology and high‐throughput screening platforms. A mussel‐inspired cytocompatible encapsulation method for achieving a “cell‐division control” with cross‐linked layer‐by‐layer (LbL) shells is developed. Catechol‐grafted polyethyleneimine and hyaluronic acid are chosen as polyelectrolytes for the LbL process, and the cross‐linking of polyelectrolytes is performed at pH 8.5. Cell division is controlled by the number of the LbL nanolayers and cross‐linking reaction. We also suggest a new measuring unit, , for quantifying “cell‐division timing” based on microbial growth kinetics.
A thiofunctional thiazolidine is introduced as a new low‐molar‐mass building block for the introduction of cysteine residues via a thiol‐ene reaction. Allyl‐functional polyglycidol (PG) is used as a model polymer to demonstrate polymer‐analogue functionalization through reaction with the unsaturated side‐chains. A modified trinitrobenzenesulfonic acid (TNBSA) assay is used for the redox‐insensitive quantification and a precise final cysteine content can be predetermined at the polymerization stage. Native chemical ligation at cysteine‐functional PG is performed as a model reaction for a chemoselective peptide modification of this polymer. The three‐step synthesis of the thiofunctional thiazolidine reactant, together with the standard thiol‐ene coupling and the robust quantification assay, broadens the toolbox for thiol‐ene chemistry and offers a generic and straightforward approach to cysteine‐functional materials.
Novel supramolecular phosphorescent polymers (SPPs) are synthesized as a new class of solution‐processable electroluminescent emitters. The formation of these SPPs takes advantage of the efficient non‐bonding assembly between bis(dibenzo‐24‐crown‐8)‐functionalized iridium complex monomer and bis(dibenzylammonium)‐tethered co‐monomer, which is monitored by 1H NMR spectroscopy and viscosity measurements. These SPPs show good film morphology and an intrinsic glass transition with a Tg of 94–116 °C. Noticeably, they are highly photoluminescent in solid state with quantum efficiency up to ca. 78%. The photophysical and electroluminescent properties are strongly dependent on the molecular structures of the iridium complex monomers.
In this communication, a mild, efficient, and generalized polycondensation route is developed for poly(disulfide)s from commercially available monomers 2,2′‐dithiodipyridine and 1,6‐hexanedithiol. Using the stoichiometric imbalance between the two monomers, it is possible to produce telechelic poly(disulfide)s of predictable molecular weight with reactive pyridyl disulfide groups at both the terminals of the chain. The two terminal pyridyl disulfide groups can be quantitatively replaced by a functional thiol using selective thiol‐disulfide exchange and thus produces functional telechelic poly(disulfide)s, which can be used as a macroinitiator to initiate ring‐opening polymerization of a cyclic lactide monomer generating an ABA‐type triblock copolymer with degradable B block.
A linear supramolecular polymer based on the self‐assembly of an easily available copillar[5]arene monomer is efficiently prepared, which is evidenced by the NMR spectroscopy, viscosity measurement, and DOSY experiment. The single‐crystal X‐ray analysis reveals that the polymerization of the AB‐type monomer is driven by the quadruple CH•••π interactions and one CH•••O interaction.
A simple process is developed to fabricate metallo‐supramolecular nanogels (MSNs) by the metallo‐supramolecular‐coordinated interaction between histidine and iron‐meso‐tetraphenylporphin. MSNs are composed of histidine‐modified dextran (DH) and iron‐meso‐tetraphenylporphin (Fe–Por) and exhibit excellent biocompatibility and stability. MSNs show pH responsiveness in the intracellular mildly acidic environment, which has great potential for acid‐triggered drug release delivery. In vitro drug release profiles demonstrate that the pH‐dependent disassembly of MSNs to histidine and Por results in a quicker release rate of loaded‐DOX at pH 5.3, while at pH 7.4 MSNs could hinder the release of loaded‐DOX due to the enhanced stability of MSNs.
The ruthenium benzimidazolylidene‐based N‐heterocyclic carbene (NHC) complex 4 catalyzes the direct dehydrogenative condensation of primary alcohols into esters and primary alcohols in the presence of amines to the corresponding amides in high yields. This efficient new catalytic system shows a high selectivity towards the conversion of diols to polyesters and of a mixture of diols and diamines to polyamides. The only side product formed in this reaction is molecular hydrogen. Remarkable is the conversion of hydroxytelechelic polytetrahydrofuran ( = 1000 g mol−1)—a polydispers starting material—into a hydrolytically degradable polyether with ester linkages ( = 32 600 g mol−1) and, in the presence of aliphatic diamines, into a polyether with amide linkages in the back bone ( = 16 000 g mol−1).
Polyamides are very important polymers that find applications from commodities up to the automotive and biomedical sectors, and their impact is continuously growing. The synthesis of structurally significant, chiral, and sustainable polyamides is described via a new, convenient, and solvent‐free anionic polymerization of a biobased ε‐lactam, which is obtained from the renewable terpenoid ketone l ‐menthone in a one‐step synthesis. These polyamides are shown to have outstanding structural and thermal properties, which are thus introduced via the structure and chirality of the natural lactam monomer and which are discussed and compared with those of petroleum‐based, established, and commercial polyamide Nylon‐6. X‐ray data reveal a remarkable degree of crystallinity in these green polymers and emphasize the impact of their structural features on the resulting properties.
1,5,7‐Triazabicyclo[4.4.0]dec‐5‐ene (TBD)‐catalyzed polycondensation reactions of fatty acid derived dimethyl dicarbamates and diols are introduced as a versatile, non‐isocyanate route to renewable polyurethanes. The key step for the synthesis of dimethyl carbamate monomers from plant‐oil‐derived dicarboxylic acids is based on a sustainable base‐catalyzed Lossen rearrangement. The formed polyurethanes with molecular weights up to 25 kDa are characterized by SEC, DSC, and NMR analysis.
The modulation of the cloud point of aqueous poly(N,N‐diethylacrylamide) solutions via the formation of supramolecular cyclodextrin complexes with hydrophobic end groups, namely adamantyl, tert‐butyl phenyl and azobenzene, synthesized via RAFT polymerization is described. The dependence of the apparent cloud points after cyclodextrin complexation is investigated with respect to the type and quantity of the guest end group, the polymer chain length and the cyclodextrin/end group ratio. Furthermore, the effect is reversed via the addition of guest molecules or via biocompatible enzymatic degradation of the cyclodextrins entire.
Hierarchical semicrystalline block copolymer nanoparticles are produced in a segmented gas‐liquid microfluidic reactor with top‐down control of multiscale structural features, including nanoparticle morphologies, sizes, and internal crystallinities. Control of multiscale structure on disparate length scales by a single control variable (flow rate) enables tailoring of drug delivery nanoparticle function including release rates.
A copolymer from N‐isopropylacryl amide (NIPAAm) and N‐homocysteine thiolactone acrylamide (TlaAm), prepared by RAFT polymerization, is reacted with various amines, bearing alkyl residues of increasing length (n‐propylamine, n‐hexylamine, and n‐dodecylamine) to liberate the corresponding thiol, which is consequently reacted in situ with 2‐bromoethyl‐2′,3′,4′,6′‐tetra‐O‐acetyl‐α‐d ‐mannopyranoside. The resulting double‐modified graft copolymers show characteristic self‐assembly behavior due to their amphiphilic nature, affording glycopolymer‐based nanoparticles. While the n‐propylamine‐derived amphiphiles mainly lead to micelles (30 nm), the n‐hexylamine adducts give rise to larger vesicles (200–600 nm). Longer alkyl amines result in the formation of large compound micelles. The assembled nanoparticles are bioactive and interact effectively with Concanavalin A (ConA).
