TY - JOUR A1 - Mazurek-Budzyńska, Magdalena A1 - Behl, Marc A1 - Neumann, Richard A1 - Lendlein, Andreas T1 - 4D-actuators by 3D-printing combined with water-based curing JF - Materials today. Communications N2 - The shape and the actuation capability of state of the art robotic devices typically relies on multimaterial systems from a combination of geometry determining materials and actuation components. Here, we present multifunctional 4D-actuators processable by 3D-printing, in which the actuator functionality is integrated into the shaped body. The materials are based on crosslinked poly(carbonate-urea-urethane) networks (PCUU), synthesized in an integrated process, applying reactive extrusion and subsequent water-based curing. Actuation capability could be added to the PCUU, prepared from aliphatic oligocarbonate diol, isophorone diisocyanate (IPDI) and water, in a thermomechanical programming process. When programmed with a strain of epsilon(prog) = 1400% the PCUU networks exhibited actuation apparent by reversible elongation epsilon'(rev) of up to 22%. In a gripper a reversible bending epsilon'(rev)((be)(nd)()) in the range of 37-60% was achieved when the actuation temperature (T-high) was varied between 45 degrees C and 49 degrees C. The integration of actuation and shape formation could be impressively demonstrated in two PCUU-based reversible fastening systems, which were able to hold weights of up to 1.1 kg. In this way, the multifunctional materials are interesting candidate materials for robotic applications where a freedom in shape design and actuation is required as well as for sustainable fastening systems. KW - 4D-actuation KW - 3D-printing KW - Ink KW - Gripper KW - Fastener Y1 - 2022 U6 - https://doi.org/10.1016/j.mtcomm.2021.102966 SN - 2352-4928 VL - 30 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Tartivel, Lucile A1 - Blocki, Anna M. A1 - Braune, Steffen A1 - Jung, Friedrich A1 - Behl, Marc A1 - Lendlein, Andreas T1 - An Inverse shape-memory hydrogel scaffold switching upon cooling in a tissue-tolerated temperature range JF - Advanced materials interfaces N2 - Tissue reconstruction has an unmet need for soft active scaffolds that enable gentle loading with regeneration-directing bioactive components by soaking up but also provide macroscopic dimensional stability. Here microporous hydrogels capable of an inverse shape-memory effect (iSME) are described, which in contrast to classical shape-memory polymers (SMPs) recover their permanent shape upon cooling. These hydrogels are designed as covalently photo cross-linked polymer networks with oligo(ethylene glycol)-oligo(propylene glycol)-oligo(ethylene glycol) (OEG-OPG-OEG) segments. When heated after deformation, the OEG-OPG-OEG segments form micelles fixing the temporary shape. Upon cooling, the micelles dissociate again, the deformation is reversed and the permanent shape is obtained. Applicability of this iSME is demonstrated by the gentle loading of platelet-rich plasma (PRP) without causing any platelet activation during this process. PRP is highly bioactive and is widely acknowledged for its regenerative effects. Hence, the microporous inverse shape-memory hydrogel (iSMH) with a cooling induced pore-size effect represents a promising candidate scaffold for tissue regeneration for potential usage in minimally invasive surgery applications. KW - active scaffold KW - critical micellation temperature KW - hydrogel KW - inverse KW - shape-memory effect KW - platelet-rich plasma Y1 - 2022 U6 - https://doi.org/10.1002/admi.202101588 SN - 2196-7350 VL - 9 IS - 6 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Liang, Xiao A1 - Behl, Marc A1 - Lendlein, Andreas T1 - Dihydroxy terminated teroligomers from morpholine-2,5-diones JF - European polymer journal : EPJ N2 - Oligodepsipeptides (ODPs) attract increasing attention as degradable materials in controlled drug delivery or as building blocks for nano-carriers. Their strong intermolecular interactions provide high stability. Tailoring the side groups of the amino acid repeating units to achieve a strong affinity to particular drugs allows a high drug-loading capacity. Here we describe synthesis and characterization of dihydroxy terminated teroligodepsipeptides (ter-ODPs) by ring-opening copolymerization (ROP) of three different morpholine-2,5-diones (MDs) in bulk in order to provide a set of teroligomers with structural variation for drug release or transfection. Ter-ODPs with equivalent co-monomer feed ratios were prepared as well as ter-ODPs, in which the co-monomer feed ratio was varied between 9 mol% and 78 mol%. Ter-ODPs were synthesized by ROP using 1,1,10,10-tetra-n-butyl-1,10-distanna-2,9,11,18-tetraoxa-5,6,14,15-tetrasulfur-cyclodecane (tin(IV) alkoxide) that was obtained by the reaction of dibutyl tin(II) oxide with 2-hydroxyethyl disulfide. The number average molecular weight (M-n) of ter-ODPs, determined by H-1 NMR and gel permeation chromatography (GPC), ranged between 4000 g center dot mol(-1) and 8600 g center dot mol(-1). Co-monomer compositions in ter-ODPs could be controlled by changing the feed ratio of co-monomers as observed by H-1 NMR spectroscopy and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The amount of remaining monomers as determined by H-1 NMR could be kept below 1 wt%. Macrocycles as main sources of byproducts as determined from MALDI-TOF-MS measurements were significantly lower as compared to polymerization by Sn(Oct)(2). Glass-transition temperature (T-g) of ter-ODPs ranged between 59 degrees C and 70 degrees C. KW - Ring-opening polymerization KW - Tin octanoate KW - Morpholindione KW - Depsipeptide KW - Random copolymer KW - Telechel Y1 - 2021 U6 - https://doi.org/10.1016/j.eurpolymj.2020.110189 SN - 0014-3057 VL - 143 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Behl, Marc A1 - Balk, Maria A1 - Mansfeld, Ulrich A1 - Lendlein, Andreas T1 - Phase morphology of multiblock copolymers differing in sequence of blocks JF - Macromolecular materials and engineering N2 - The chemical nature, the number length of integrated building blocks, as well as their sequence structure impact the phase morphology of multiblock copolymers (MBC) consisting of two non-miscible block types. It is hypothesized that a strictly alternating sequence should impact phase segregation. A library of well-defined MBC obtained by coupling oligo(epsilon-caprolactone) (OCL) of different molecular weights (2, 4, and 8 kDa) with oligotetrahydrofuran (OTHF, 2.9 kDa) via Steglich esterification results in strictly alternating (MBCalt) or random (MBCran) MBC. The three different series has a weight average molecular weight (M-w) of 65 000, 165 000, and 168 000 g mol(-1) for MBCalt and 80 500, 100 000, and 147 600 g mol(-1) for MBCran. When the chain length of OCL building blocks is increased, the tendency for phase segregation is facilitated, which is attributed to the decrease in chain mobility within the MBC. Furthermore, it is found that the phase segregation disturbs the crystallization by causing heterogeneities in the semi-crystalline alignment, which is attributed to an increase of the disorder of the OCL semi-crystalline alignment. KW - electron microscopy KW - multiblock copolymers KW - phase morphology KW - polymer KW - libraries KW - sequence structures KW - wide angle x‐ ray scattering Y1 - 2021 U6 - https://doi.org/10.1002/mame.202000672 SN - 1439-2054 VL - 306 IS - 3 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Liang, Xiao A1 - Behl, Marc A1 - Lützow, Karola A1 - Lendlein, Andreas T1 - Cooligomers from morpholine-2,5-dione and para-dioxanone and catalyst complex SnOct(2)/2-hydroxyethyl sulfide JF - MRS advances : a journal of the Materials Research Society (MRS) N2 - Complexes from catalysts and initiator can be used to insert a specific number of additional chemical functional groups in (co)polymers prepared by ring-opening polymerization (ROP) of lactones. We report on the synthesis of cooligomers from sec-butyl-morpholine-2,5-dione (SBMD) and para-dioxanone (PDX) by ROP with varied feed ratios in the bulk using the catalyst complex SnOct(2)/2-hydroxyethyl sulfide. M-n of the cooligomers (determined by GPC) decreased with decreasing SBMD feed ratio from 4200 +/- 420 to 800 +/- 80 g mol(-1). When the feed ratio was reduced from 80 to 50 mol% the molar ratio of SBMD of the cooligomers (determined by H-1-NMR) remained nearly unchanged between 81 and 86 mol% and was attributed to a higher reactivity of SBMD. This assumption was confirmed by fractionation of GPC, in which an increase of SBMD with increasing molecular weight was observed. The catalyst/initiator system provides a high potential to create orthogonal building blocks by cleavage of the sulfide bond. Y1 - 2021 U6 - https://doi.org/10.1557/s43580-021-00082-5 SN - 2059-8521 VL - 6 IS - 32 SP - 764 EP - 768 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Farhan, Muhammad A1 - Behl, Marc A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Origami hand for soft robotics driven by thermally controlled polymeric fiber actuators JF - MRS communications / a publication of the Materials Research Society N2 - Active fibers can serve as artificial muscles in robotics or components of smart textiles. Here, we present an origami hand robot, where single fibers control the reversible movement of the fingers. A recovery/contracting force of 0.2 N with a work capacity of 0.175 kJ kg(-1) was observed in crosslinked poly[ethylene-co-(vinyl acetate)] (cPEVA) fibers, which could enable the bending movement of the fingers by contraction upon heating. The reversible opening of the fingers was attributed to a combination of elastic recovery force of the origami structure and crystallization-induced elongation of the fibers upon cooling. KW - Robotics KW - Polymer KW - Fiber KW - Actuation KW - Shape-memory Y1 - 2021 U6 - https://doi.org/10.1557/s43579-021-00058-4 SN - 2159-6859 SN - 2159-6867 VL - 11 IS - 4 SP - 476 EP - 482 PB - Springer CY - Berlin ER - TY - JOUR A1 - Balk, Maria A1 - Behl, Marc A1 - Nöchel, Ulrich A1 - Lendlein, Andreas T1 - Enzymatically triggered Jack-in-the-box-like hydrogels JF - ACS applied materials & interfaces / American Chemical Society N2 - Enzymes can support the synthesis or degradation of biomacromolecules in natural processes. Here, we demonstrate that enzymes can induce a macroscopic-directed movement of microstructured hydrogels following a mechanism that we call a "Jack-in-the-box" effect. The material's design is based on the formation of internal stresses induced by a deformation load on an architectured microscale, which are kinetically frozen by the generation of polyester locking domains, similar to a Jack-in-thebox toy (i.e., a compressed spring stabilized by a closed box lid). To induce the controlled macroscopic movement, the locking domains are equipped with enzyme-specific cleavable bonds (i.e., a box with a lock and key system). As a result of enzymatic reaction, a transformed shape is achieved by the release of internal stresses. There is an increase in entropy in combination with a swelling-supported stretching of polymer chains within the microarchitectured hydrogel (i.e., the encased clown pops-up with a pre-stressed movement when the box is unlocked). This utilization of an enzyme as a physiological stimulus may offer new approaches to create interactive and enzyme-specific materials for different applications such as an optical indicator of the enzyme's presence or actuators and sensors in biotechnology and in fermentation processes. KW - enzyme KW - hydrogels KW - stimuli-sensitive materials KW - shape change KW - poly(e-caprolactone) KW - switch KW - microporous Y1 - 2021 U6 - https://doi.org/10.1021/acsami.1c00466 SN - 1944-8244 SN - 1944-8252 VL - 13 IS - 7 SP - 8095 EP - 8101 PB - American Chemical Society CY - Washington, DC ER - TY - JOUR A1 - Behl, Marc A1 - Balk, Maria A1 - Lützow, Karola A1 - Lendlein, Andreas T1 - Impact of block sequence on the phase morphology of multiblock copolymers obtained by high-throughput robotic synthesis JF - European polymer journal : EPJ N2 - The chemical nature, the number length of integrated building blocks, as well as their sequence structure impact the phase morphology of multiblock copolymers (MBC) consisting of two non-miscible block types. We hypothesized that a strictly alternating sequence should favour phase segregation and in this way the elastic properties. A library of well-defined MBCs composed of two different hydrophobic, semi-crystalline blocks providing domains with well-separated melting temperatures (T(m)s) were synthesized from the same type of precursor building blocks as strictly alternating (MBCsalt) or random (MBCsran) MBCs and compared. Three different series of MBCsalt or MBCsran were synthesized by high-throughput synthesis by coupling oligo(e-caprolactone) (OCL) of different molecular weights (2, 4, and 8 kDa) with oligotetrahydrofuran (OTHF, 2.9 kDa) via Steglich esterification in which the molar ratio of the reaction partners was slightly adjusted. Maximum of weight average molecular weight (M-w) were 65,000 g center dot mol(-1), 165,000 g center dot mol(-1), and 168,000 g center dot mol(-1) for MBCsalt and 80,500 g center dot mol(-1), 100,000 g center dot mol(-1), and 147,600 g center dot mol(-1) for MBCsran. When Mw increased, a decrease of both Tms associated to the melting of the OCL and OTHF domains was observed for all MBCs. T-m (OTHF) of MBCsran was always higher than Tm (OTHF) of MBCsalt, which was attributed to a better phase segregation. In addition, the elongation at break of MBCsalt was almost half as high when compared to MBCsran. In this way this study elucidates role of the block length and sequence structure in MBCs and enables a quantitative discussion of the structure-function relationship when two semi-crystalline block segments are utilized for the design of block copolymers. KW - Multiblock copolymers KW - Sequence structure KW - Phase morphology KW - Polymer KW - library KW - Robotic synthesis KW - High-throughput Y1 - 2021 U6 - https://doi.org/10.1016/j.eurpolymj.2020.110207 SN - 0014-3057 SN - 1873-1945 VL - 143 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Zhang, Pengfei A1 - Rešetič, Andraž A1 - Behl, Marc A1 - Lendlein, Andreas T1 - Multifunctionality in polymer networks by dynamic of coordination bonds JF - Macromolecular chemistry and physics N2 - The need for multifunctional materials is driven by emerging technologies and innovations, such as in the field of soft robotics and tactile or haptic systems, where minimizing the number of operational components is not only desirable, but can also be essential for realizing such devices. This study report on designing a multifunctional soft polymer material that can address a number of operating requirements such as solvent resistance, reshaping ability, self-healing capability, fluorescence stimuli-responsivity, and anisotropic structural functions. The numerous functional abilities are associated to rhodium(I)-phosphine coordination bonds, which in a polymer network act with their dynamic and non-covalently bonded nature as multifunctional crosslinks. Reversible aggregation of coordination bonds leads to changes in fluorescence emission intensity that responds to chemical or mechanical stimuli. The fast dynamics and diffusion of rhodium-phosphine ions across and through contacting areas of the material provide for reshaping and self-healing abilities that can be further exploited for assembly of multiple pieces into complex forms, all without any loss to material-sensing capabilities. KW - assembly capabilities KW - fluorescence stimuli‐ responsivity KW - multiple functions KW - reshaping abilities KW - rhodium(I)– phosphine KW - coordination bonds KW - solvent resistance Y1 - 2021 U6 - https://doi.org/10.1002/macp.202000394 SN - 1521-3935 VL - 222 IS - 3 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Folikumah, Makafui Yao A1 - Behl, Marc A1 - Lendlein, Andreas T1 - Thiol-Thioester exchange reactions in precursors enable pH-triggered hydrogel formation JF - Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences N2 - Bio-interactive hydrogel formation in situ requires sensory capabilities toward physiologically relevant stimuli. Here, we report on pH-controlled in situ hydrogel formation relying on latent cross-linkers, which transform from pH sensors to reactive molecules. In particular, thiopeptolide/thio-depsipeptides were capable of pH-sensitive thiol-thioester exchange reactions to yield a,co-dithiols, which react with maleimide-functionalized multi-arm polyethylene glycol to polymer networks. Their water solubility and diffusibility qualify thiol/thioester-containing peptide mimetics as sensory precursors to drive in situ localized hydrogel formation with potential applications in tissue regeneration such as treatment of inflamed tissues of the urinary tract. Y1 - 2021 U6 - https://doi.org/10.1021/acs.biomac.0c01690 SN - 1525-7797 SN - 1526-4602 VL - 22 IS - 5 SP - 1875 EP - 1884 PB - American Chemical Society CY - Washington ER -