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A novel triblock macromolecular architecture based on cyclodextrin (CD) complexation is presented. A CDfunctionalized biocompatible poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA) building block (3800 ≤ M n ≤ 10 600 g mol −1 ; 1.29 ≤ Đ M ≤ 1.46) and doubly guestcontaining poly(N,N-dimethylacrylamide) (PDMAAm) (6400 ≤ M n ≤ 15 700 g mol −1 ; 1.06 ≤ Đ M ≤ 1.15) and poly(N,Ndiethylacrylamide) (PDEAAm) (5400 ≤ M n ≤ 12 100 g mol −1 ; 1.11 ≤ Đ M ≤ 1.33) segments were prepared via reversible addition−fragmentation chain transfer (RAFT) polymerization and subsequently utilized for the formation of a well-defined supramolecular ABA triblock copolymer. The block formation was evidenced via dynamic light scattering (DLS), nuclear Overhauser effect spectroscopy (NOESY), and turbidity measurements. Furthermore, the connection of the blocks was proven to be temperature responsive andin the case of azobenzene guestsresponsive to the irradiation with UV light. The application of these stimuli leads to the disassembly of the triblock copolymer, which was shown to be reversible. In the case of PDEAAm containing triblock copolymers, the temperatureinduced aggregation was investigated as well.

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The synthesis of a new glycomonomer based on mannose, prepared via CuAAC, is reported. The resulting 1,2,3-triazole linkage between mannose and the polymer backbone ensures the formation of highly stable glycopolymers, which will not undergo hydrolysis. The monomer 2'-(4-vinyl-[1,2,3]-triazol-1-yl)ethyl-O-alpha-D-mannopyranoside was polymerized in the presence of a RAFT agent - 3-benzylsulfanylthiocarbonylsulfanyl propionic acid - to yield well-defined polymers with molecular weights up to 51,500 g mol(-1) and a PDI of 1.16. The resulting polymer was employed as a macroRAFT agent in the polymerization of NIPAAm in order to generate thermo-responsive block copolymers, which undergo reversible micelle formation at elevated temperatures. The rapid interaction between the polymers prepared and ConA confirms the high affinity of these structures to proteins. While the linear glycopolymers already undergo a fast complexation with ConA, the reported rates have found to be exceeded by the micellar glycopolymer structure presented in the current contribution.

We report the formation of a novel class of supramolecular miktoarm star polymers via cyclodextrin host-guest chemistry. Reversible addition-fragmentation chain transfer polymerization from difunctional guest-or alkyne-containing chain transfer agents and copper(I)-catalyzed azide-alkyne cycloaddition leads to hostand guest-containing acrylamido polymers, namely poly(N,Ndimethylacrylamide) and poly(N,N-diethylacrylamide). Subsequently, a supramolecular miktoarm star polymer was formed and characterized via dynamic light scattering and rotating frame nuclear Overhauser effect spectroscopy.The generation of novel macromolecular architectures utilizing the concept of supramolecular chemistry has driven synthetic polymer chemistry significantly in the last few years. 1 Hydrogen bonding, 2,3 metal complexes 4 and inclusion complexes 5 are widely employed in that regard. Cyclodextrins (CDs) are an important class of supramolecular hosts that have the ability to form inclusion complexes. This ability has found manifold utilization in polymer chemistry, e.g. for drug-delivery, 6 to dissolve hydrophobic monomers 7 or to impart water solubility to hydrophobic chain-transfer agents. 8 From the view of macromolecular architectures CDs give the opportunity for the formation of macromolecular architectures that are governed by supramolecular interactions in an aqueous environment. 9 Examples for the utilization of CDs for the formation of complex macromolecular architectures cover a broad range of architectures, e.g. linear diblockcopolymers, 10-14 supramolecular gels, 15,16 star polymers, 17 CDcentered star polymers connected to linear polymers 18,19 or supramolecular grafts for polymer brushes. 20,21 Herein, we report the formation of supramolecular miktoarm star polymers, i.e. star polymers that have arms consisting of more than one polymer type, utilizing CD-and adamantyl-functionalized acrylamido polymers. The precursor polymers were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization 22,23 -based on a novel two-arm adamantyl bearing trithiocarbonate -of N,N-dimethylacrylamide (DMAAm) and N,Ndiethylacrylamide (DEAAm) and were thoroughly characterized via ESI-MS, NMR and size exclusion chromatography (SEC) in N,Ndimethylacetamide (DMAc). The subsequent formation of the supramolecular complex in water was proven via 2D rotating frame nuclear Overhauser effect spectroscopy (ROESY) NMR and is supported by dynamic light scattering (DLS) data.To achieve a mid-chain guest-functionalized polymer a RAFT agent with an adamantyl moiety between two trithiocarbonategroups was synthesized (Schemes 1 and S1 †). The prominent Scheme 1 Synthetic pathway for the supramolecular miktoarm star polymer: poly(DEAAm) is depicted in black, poly(DMAAm) is depicted in red, the CD moiety is depicted orange and the adamantyl group is depicted in dark blue.

The first aqueous reversible addition–fragmentation transfer (RAFT) polymerization of N,N-dimethylacrylamide (DMAAm), N,N-diethylacrylamide (DEAAm), and N-isopropylacrylamide (NIPAAm) utilizing host/guest complexes of cyclodextrin and hydrophobic chain transfer agents (CTAs) at 25 °C is described. Three novel guest-functionalized CTAs, namely 4-(tert-butyl)phenyl 2-(((ethylthio)carbonothioyl)thio)-2-methylpropanoate, bis(4-tert-butyl)benzyl carbonotrithioate, and benzyl (3-((4-(tert-butyl)phenyl)amino)-3-oxopropyl)carbonotrithioate, were synthesized and employed in aqueous RAFT polymerizations. The presented technique allows for the facile preparation of hydrophilic polymers with hydrophobic end groups in aqueous environments. The living/controlled radical polymerization afforded high molecular masses (7500 ≤ M n ≤ 116 000 g mol–1 for poly(DMAAm), 2500 ≤ M n ≤ 150 000 g mol–1 for poly(DEAAm), and 4000 ≤ M n ≤ 50 000 g mol–1 for poly(NIPAAm)) with low PDIs (1.06 ≤ PDI ≤ 1.54 for poly(DMAAm), 1.05 ≤ PDI ≤ 1.39 for poly(DEAAm), and 1.15 ≤ PDI ≤ 1.46 for poly(NIPAAm)). To confirm the living character of the polymerizations, kinetic measurements were undertaken that evidence a linear evolution of molecular weight with conversion. Furthermore, chain extensions were carried out that indicate a very high reinitiation efficiency (poly(DMAAm): from 10 500 to 97 500 g mol–1, PDI = 1.08; poly(DEAAm): from 8500 to 83 000 g mol–1, PDI = 1.13; poly(NIPAAm): from 9000 to 90 000 g mol–1, PDI = 1.11). The resulting polymers were thoroughly characterized via N,N-dimethylacetamide (DMAc) size exclusion chromatography, 1H NMR, and electrospray ionization-mass spectrometry (ESI-MS).

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.

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