Research Field 5

Thümmler, J. F., et al. Macromol. Rapid. Commun., 2022, DOI:https://doi.org/10.1002/marc.202200618

Controlling the internal structures of single-chain nanoparticles (SCNPs) is an important factor for their targeted chemical design and synthesis, especially in view of nanosized compartments presenting different local environments as a main feature to control functionality. We here design SCNPs (sized 6 – 12 nm) bearing near-infrared fluorescent dyes embedded in hydrophobic compartments for use as contrast agents in pump–probe photoacoustic (PA) imaging. SCNPs with the dye molecules accumulate at the core and show a nonlinear PA response as a function of pulse energy—a property that can be exploited as a contrast mechanism in molecular PA tomography.

Wu, Y., et al. Polym. Chem., 2022, DOI:https://pubs.rsc.org/en/content/articlelanding/2022/py/d1py01634b

Integrating biomedical applications (e.g., drug delivery) into supramolecular chemistry is a promising strategy. This work targets the construction of hydrogen-bonded (H-bonded) supramolecular polymeric micelles loaded with chemotherapy drugs (carmofur) and photothermal agents (IR780) for combined chemo-photothermal therapies (CT/PTT).

Roos, A. H., et al. Soft Matter, 2021, DOI:https://doi.org/10.1039/D1SM00582K

We characterize temperature-dependent macroscopic and nanoscopic phase transitions and nanoscopic pre-transitions of water-soluble single chain nanoparticles (SCNPs). We analyze the temperature-dependent phase transitions of spin-labeled SCNPs by rigorous spectral simulations of a series of multicomponent EPR-spectra that derive from the nanoinhomogeneities (1) that are due to the single-chain compartmentation in SCNPs and (2) the transformation upon temperature change due to the LCST behavior. These transitions of the SCNPs and their respective polymer precursors can be monitored and understood on the nanoscale by following EPR-spectroscopic parameters like hyperfine couplings that depend on the surrounding solvent molecules or Heisenberg spin exchange.

Wang, H., et. al. J. Polymer Chemistry, 2021, 12, 6300-6306, https://doi.org/10.1039/D1PY01061A

Giant vesicles represent an extremely useful system to mimick biomembranes. By designing a hydrogen-bonding (H-bonding) amphiphilic ABA triblock copolymer and introducing 2,6-diaminopyridine (DAP) moieties as pendant groups within the middle hydrophobic block, we demonstrate a straightforward and effective self-assembly strategy to form giant vesicles (~3 μm in diameter) via a combination of H-bonding and amphiphilic interactions. This study provides a new opportunity for the design of supramolecular polymers, serving as polymeric vesicle scaffolds in material design and may act as red-blood-cell-like container in delivery and microreactor applications. Published with a permission of the Polymer Chemistry 2021.

Hoffmann, J.F., et al. Angewandte Chemie, International Edition, 2021, accepted, https://doi.org/10.1002/anie.202015179

The internal structure of single-chain nanoparticles (SCNPs) has been investigated, forming nanosized domains preformed during the crosslinking process. We present proof for the presence of nano-compartments within SCNPs via a combination of electron paramagnetic resonance (EPR) and fluorescence spectroscopy. A novel strategy to encapsulate labels within such water dispersible SCNPs is presented.

Rupp, H., et. al. Macromolecular Rapid Communications, 2021, https://doi.org/10.1002/marc.202000450

The preparation and characterization of mechanoresponsive, 3D-printed composites is reported using a dual-printing setup for both, liquid dispensing and fused-deposition-modeling. The here reported stress‐sensing materials are based on high- and low molecular weight mechanophores, including  poly(e-caprolactone)-, polyurethane-, and alkyl(C11)-based latent copper(I)bis(N‐heterocyclic carbenes), which can be activated by compression to trigger a fluorogenic, copper(I)-catalyzed azide/alkyne “click”-reaction (CuAAC) of  an azide-functionalized fluorescent dye inside a bulk polymeric material. The low-molecular weight mechanophores bearing the alkyl-C11 chains displayed the best printability, yielding a useful mechanochemical response after the 3D-printing process. © 2020 The Authors. Published by Wiley‐VCH GmbH

Döhler, D., et. al. ACS Applied Polymer Materials, 2020, 4127, https://dx.doi.org/10.1021/acsapm.0c00755

We present a comprehensive investigation of mechanical properties of supramolecular polymer networks with rationally developed multistrength hydrogen-bonding interactions. Self-healing poly(dimethylsiloxane) (PDMS)-based elastomers with varying elasticity, fracture toughness, and the ability to dissipate strain energy through the reversible breakage and re-formation of the supramolecular interactions were obtained. By changing the ratio between isophorone diisocyanate (IU), 4,4′-methylenebis(cyclohexyl isocyanate) (MCU), and 4,4′-methylenebis(phenyl isocyanate) (MPU) and by varying the molecular weight of the PDMS precursor, we obtained a library of poly(urea)s to study the interplay of mechanical performance and self-healability. Selected poly(urea)s could be processed via 3D printing by the conventional extrusion method, obtaining dimensionally stable and freestanding objects. Copyright © 2020, American Chemical Society

Rupp, H., et al. Advanced Materials Technology, 2020, 2000509, https://doi.org/10.1002/admt.202000509

3D-printing of multi-component materials as an advantageous method over traditional mold casting methods is demonstrated, developing small core-shell capsule composites fabricated by a two-step 3D-printing process. We here report the 3D-printing of a capsule-based multicomponent material using a two print-head system (fused deposition modeling extruder and a liquid inkjet print head), to embed micro-sized capsules in sizes ranging from 100 – 800 µm, located within the thermoplastic polymer poly(ε-caprolactone) (PCL) As a proof of concept novel “click”-reaction systems, used in self-healing and stress-detection applications, are manufactured, in which PCL composites with nano- and micro-fillers are combined with reactive, encapsulated liquids. Copyright © 2020 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim

Rupp, H., et al. Macromolecular Rapid Communications 2019,1900467, DOI: https://doi.org/10.1002/marc.201900467.

3D printing of linear and three-arm star supramolecular polymers with attached hydrogen bonds and their nanocomposites is reported. The linear and three-arm star poly(isobutylene)s PIB-B2 (Mn = 8500 g mol ^-1), PIB-B3 (Mn = 16 000 g mol ^-1), and linear poly(ethylene glycol)s PEG-B2 (Mn = 900 g mol^-1, 8500 g mol ^-1) are prepared and then probed by melt-rheology to adjust the viscosity to address the proper printing window. A blend of the linear polymer PIB-B2 and the three-arm star polymer PIB-B3 (ratio ≈ 3/1 mol) reaches an even higher structural stability, able to build free-standing structures. Reproduced by permission. Copyright © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.