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Quantification of the stimuli-responsive phase transition in polymers is topical and important for the understanding and development of novel stimuli-responsive materials. The temperature-induced phase transition of poly(N-isopropylacrylamide) (PNIPAm) with one thiol end group depends on the confinement—free polymer or polymer brush—on the molecular weight and on the nature of the second end. This paper describes the synthesis of heterotelechelic PNIPAm of different molecular weights with a thiol end group—that specifically binds to gold nanorods and a hydrophilic NIPAm end group by reversible addition-fragmentation chain-transfer polymerization. Proton high-resolution magic angle sample spinning NMR spectra are used as an indicator of the polymer chain conformations. The characteristics of phase transition given by the transition temperature, entropy, and width of transition are obtained by a two-state model. The dependence of thermodynamic parameters on molecular weight is compared for hydrophilic and hydrophobic end functional-free polymers and brushes.

The preparation of multifunctional polymers and block copolymers by a straightforward one-pot reaction process that combines enzymatic transacylation with light-controlled polymerization is described. Functional methacrylate monomers are synthesized by enzymatic transacylation and used in situ for light-controlled polymerization, leading to multifunctional methacrylate-based polymers with well-defined microstructure.

Herein, we report synthesis and self-association properties of amphiphilic double-comb polymers with polyglycidol backbones. First, a bifunctional polyglycidol precursor is synthesized via monomer activated anionic polymerization. Next, two efficient and orthogonal polymer analogous reactions are carried out for grafting hydrophilic oligoethylene glycol side chains and hydrophobic linear aliphatic side-chains. The polymers are analyzed by means of NMR, GPC, and DSC. From the DSC analysis of the bulk samples it is evident that aliphatic side chains segregate from the polar backbone and thus crystallize. Furthermore, in aqueous media the double-comb polymers spontaneously self-assemble to form a multilayer structure. The present results pave a way to tailor and design amphiphilic polymers based on glycidols. Major advantages are spontaneous self-assembly in water and the possibility to form onion polymersomes relevant to encapsulation.

Preparation, purification, and stabilization of functional (meth)acrylates with a high dipole moment are complex, laborious, and expensive processes. In order to avoid purification and stabilization of the highly reactive functional monomers, a concept of cascade reactions was developed comprising enzymatic monomer synthesis and radical polymerization. Transacylation of methyl acrylate (MA) and methyl methacrylate (MMA) with different functional alcohols, diols, and triols (1,2,6-hexanetriol and glycerol) in the presence of Novozyme 435 led to functional (meth)acrylates. After the removal of the enzyme by means of filtration, removal of excess (meth)acrylate and/or addition of a new monomer, e.g., 2-hydroxyethyl (meth)acrylate the (co)polymerization via free radical (FRP) or nitroxide mediated radical polymerization (NMP) resulted in poly[(meth)acrylate]s with predefined functionalities. Hydrophilic, hydrophobic as well as ionic repeating units were assembled within the copolymer. The transacylation of MA and MMA with diols and triols carried out under mild conditions is an easy and rapid process and is suitable for the preparation of sensitive monomers.

Phenoxycarbonyloxymethyl ethylene carbonate 4 was synthesized from glycerol carbonate and phenyl chloroformate Polyurethanes with pendant hydroxyl greups were obtained from polycondensation reactions of this AA* monomer with diamines. These polymers contan primary as well as secondary hydroxyl groups The obtained polyurethanes are amorphous materials. The glass transition temperature decreases with increasing number of methylene groups between the urethane groups.

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 (Mn = 1000 g mol(-1))--a polydispers starting material--into a hydrolytically degradable polyether with ester linkages (Mn = 32 600 g mol(-1)) and, in the presence of aliphatic diamines, into a polyether with amide linkages in the back bone (Mn = 16 000 g mol(-1) ).

In this article, a synthetic concept for the preparation of polyamides with functional side groups is described. First, the synthesis of a bis (thiolactone) monomer is shown in a concise three-step route from itaconic acid and DL-homocysteine thiolactone. The reactivity of the resulting bis (thiolactone) toward hexyl amine is examined. Next, the bis (thiolactone) is reacted as A,A-type monomer with different B,B-type comonomers (1,12-diaminododecane and 1,3- bis (aminopropyl)tetramethyldisiloxane). Ring opening of the thiolactones by the diamines leads to polyamides with pendant thiol groups. Using two diamines in different ratios, the properties of the resulting polyamides are tuned (thermal properties are determined) and different molecular weights are acquired. Subsequently, the thiol groups are reacted with methyl acrylate via Michael addition to functionalize the polyamides. Functionalization of thiol-functional polyamides using poly(ethylene glycol) monomethyl ether (mPEG) acrylates (Mn = 480 and 1700 g mol −1 ) results in water-soluble amphiphilic polyamides with molecular weights higher than 10 000 g mol −1 .

The cationic bridged zirconocene complex, [iPr(Cp)(InD)Zr(Me)(THF)][BPh 4 ] (1-BPh 4 ) was synthesized. Polymerization of methyl methacrylate with 1-BPh 4 in CH 2 Cl 2 at temperatures between -20 and 20°C led to the formation of isotactic poly(mehtyl methacrylate). The low polydispersity index of the polymer obtained and a successfull two step polymerization of methyl methacrylate with 1-BPh 4 are hints towards a living polymerization mechanism. 1 H and 13 C NMR analysis revealed an enantiomorphic site-controlled mechanism for the formation of isotactic poly(methyl methacrylate).

This review covers most of the authors' work on ring-opening polymerization and copolymerization of heterocyclic monomers during the time of their cooperation since 1985. The mechanistic aspects of anionic ring opening polymerization of cyclic carbonates with a variety of functional groups are described first. By sequential polymerization of first styrene, methyl methacrylate or suitable heterocyclic monomers and then secondly a cyclic carbonate, the site transformation is highlighted. The influence of the chemical nature of macroinitiators with identical active sites on the course of polymerization of cyclic carbonates was studied for poly(ethylene oxide), poly(tetrahydrofuran), and poly(dimethylsiloxane) macroinitiators. For the copolymerization of cyclic carbonates with lactones and lactide the dependence of the polymer microstructure on the polymerization conditions is discussed on the basis of the copolymerization mechanism. The copolymerization of cyclic carbonates with e-caprolactam and with tetramethylene urea results in an alternating copolymer, i. e. a poly(ester urethane) and an [m, n]-polyurethane, respectively, the key step being the insertion of the lactam or the cyclic urea into the carbonate chain. The cationic ring opening polymerization of cyclic six and seven membered carbamates leading to [4]- and [5]-polyurethane with uniform microstructure is reported with respect to kinetic, mechanistic, and thermodynamic aspects. This new access to [n]-polyurethanes by a chain growth reaction allows the synthesis of well defined polymer architectures with polyurethane sequences. Sequential polymerization of tetrahydrofuran and the cyclic carbamate with mono- and bifunctional initiators leads to the respective A–B and B–A–B block copolymers. Site transformation from the oxonium to the immonium active species is the key step in the polymerization mechanism. Finally, mechanistic aspects of the ring-opening polymerization of cyclic ester-amides are presented.

Di- and triblock copolymers with tetramethyleneoxy and trimethylene urethane repeating units were prepared by sequential polymerization of tetrahydrofuran (THF) and trimethylene urethane (TU) with the monofunctional initiator methyl trifluoromethanesulfonate (TfOMe) and the bifunctional initiator trifluoromethanesulfonic acid anhydride (TfOTf), respectively. The block copolymers obtained after purification show a uniform A-B resp. A-B-A microstructure as was deduced from NMR and GPC analyses. The block copolymers are semicrystalline materials with distinct melting points of the poly(THF) and the poly(TU) domains.

Copolymerization of tetramethylene urea (TeU, 1) with the cyclic carbonates 2,2-dimethyltrimethylene carbonate (DTC, 2) and ethylene carbonate (EC, 3) results in the polyurethanes 4 and 5 with an approximate number-average molecular weight of 20 000 and a polydispersity index of two. Polyurethane 4 is an amorphous material with a glass transition temperature of 26.3°C; polyurethane 5 is a semicrystalline material with a melting temperature of 208°C. Distinct copolymerization mechanisms are proposed for the formation of polyurethane 4 and 5, respectively.

The cationic ring-opening polymerization of trimethylene urethane (tetrahydro-2 H-1,3-oxazin-2-one) in the melt with methyl trifluoromethanesulfonate as initiator results in poly(trimethylene urethane) in yields of ≈70%. Under the same reaction conditions 2,2-dimethyltrimethylene urethane (5,5-dimethyltetrahydro-2H-1,3-oxazin-2-one) cannot be polymerized. Poly(2,2-dimethyltrimethylene urethane), however, was obtained via polycondensation polymerization. Both polymers exhibit a uniform microstructure as deduced from NMR spectroscopic analysis. Ring-closing depolymerization in the melt with dibutyltin dimethoxide or titanium tetraisopropoxide at 140°C results the respective monomers in yields of ≈90%.

Preparation, purification, and stabilization of functional (meth)acrylates with a high dipole moment are complex, laborious, and expensive processes. In order to avoid purification and stabilization of the highly reactive functional monomers, a concept of cascade reactions was developed comprising enzymatic monomer synthesis and radical polymerization. Transacylation of methyl acrylate (MA) and methyl methacrylate (MMA) with different functional alcohols, diols, and triols (1,2,6-hexanetriol and glycerol) in the presence of Novozyme 435 led to functional (meth)acrylates. After the removal of the enzyme by means of filtration, removal of excess (meth)acrylate and/or addition of a new monomer, e.g., 2-hydroxyethyl (meth)acrylate the (co)polymerization via free radical (FRP) or nitroxide mediated radical polymerization (NMP) resulted in poly[(meth)acrylate]s with predefined functionalities. Hydrophilic, hydrophobic as well as ionic repeating units were assembled within the copolymer. The transacylation of MA and MMA with diols and triols carried out under mild conditions is an easy and rapid process and is suitable for the preparation of sensitive monomers.

Poly(2-hydroxyethyl acrylate) (PHEA) is an interesting biomaterial with similar biocompatibility as the widespread used poly(2-hydroxyethyl methacrylate). Poly(2-hydroxypropyl acrylate) (PHPA) is a less frequently studied polymer that exhibits thermoresponsive behavior in water. Therefore, copolymers of HEA and HPA are interesting thermoresponsive polymers to evaluate as potential biomaterials. Here, we report the copolymerization kinetics of HEA and HPA by nitroxide-mediated polymerization, employing Bloc-builder ® initiator and SG-1 free nitroxide, revealing an ideal random copolymerization. Furthermore, the thermoresponsive properties of the resulting copolymers are discussed, whereby the cloud points are related to both polymer composition as well as polymer concentration.

We report the first successful block copolymerization of ethylene and methyl methacrylate using a zirconocene-based catalyst system. The catalyst is generated in situ from Me2C(Cp)(Ind)ZrMe2 and B(C6F5)3 in toluene. Block copolymerization is achieved via the sequential addition of the monomers, starting with ethylene. The composition of the block copolymer is shown to be dependent on the time allowed for ethylene polymerization. The solubility of the resulting polymers, NMR data and GPC measurements are discussed, and a polymerization mechanism is proposed.