Lowering of Electrostatic Actuator Driving Voltage and Increasing Generated Force Using Spontaneous Polarization of Ferroelectric Nematic Liquid Crystals

Advanced Physics Research, Год журнала: 2022, Номер 1(1)

Опубликована: Ноя. 11, 2022

Abstract Although electrostatic actuators have a simple structure and are lightweight, their range of application is limited because high applied voltage more than several kilovolts required for practical use. Since the force acting between electrodes an actuator determined by electric charge accumulated at electrode/dielectric interface, focus on spontaneous polarization ferroelectrics to increase charge. As ferroelectric material, nematic liquid crystal material with 5 µC cm −2 used. It demonstrated that 1.3 N generated field 0.5 MV m −1 . This 1200 times higher standard paraelectric materials dielectric constant ten. Further, responds linearly voltage, whereas it proportional square materials. The function this examined using double‐helical coil electrode fabricated 3D printer. can be successfully operated tens volts. Under 0.25 , remarkable contraction 6.3 mm occurs, corresponding 19% original length.

Язык: Английский

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Modifying the liquid crystalline chessboard tiling - Soft reticular self-assembly of side-chain fluorinated polyphiles

Journal of Materials Chemistry C, Год журнала: 2024, Номер unknown

Опубликована: Янв. 1, 2024

Combining side-chain fluorination with core-fluorination provides access to new liquid crystalline honeycombs due nano-segregation and competing tilt modes, either within or out of the crystallographic plane.

Язык: Английский

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LC-elastomers: structure -property relations and concepts to improve applicability

Liquid Crystals, Год журнала: 2022, Номер 50(7-10), С. 1129 - 1142

Опубликована: Ноя. 14, 2022

This review deals with liquid crystalline elastomers (LCEs) and focuses thereby on three aspects. At first, (i) structure–property relations to optimise the magnitude of achievable actuation are discussed then different exemptions their origin. They apply especially smectic systems a strong segregation between mesogenic core interlayer region as they found, e.g., in diluted LC-polysiloxanes. In next chapter, concepts make LCEs better applicable active elements micromachines discussed. To allow device, which stays – whole at constant temperature, incorporation ohmic heaters (electrical actuation) or suitable chromophores (photochemical is Finally, system presented can be moved around decimetre range by magnetic fields actuated locally (micrometre range) thermally photochemically induced phase transition.

Язык: Английский

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Synthesis of Silsesquioxane-linked Polyester with Liquid Crystalline Backbone Chain

Materials Today Communications, Год журнала: 2024, Номер 39, С. 109316 - 109316

Опубликована: Май 21, 2024

Язык: Английский

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Liquid Crystal Promoted Self-Assembly of Statistical Copolymers into Diverse Nanostructures with Precise Dimensions

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(45), С. 31221 - 31229

Опубликована: Ноя. 2, 2024

In both natural and synthetic systems, the segregation of multicomponent entities is vital for regulating functions ultimate usage materials. To accomplish desired properties via nanosegregation or microphase separation, great effort usually demanded in synthesis. For example, microphase-separated block copolymers rely on delicate controlled/living polymerization different monomers sequence. Here, we demonstrate that a facile one-pot copolymerization can generate statistical side-chain exhibiting well-defined diverse nanostructures. Two hemiphasmidic (or wedge-shaped) cyclooctene were designed, differing peripheral tails wedges (dodecyl vs. tetraethylene glycol), with lengths ca. 1 nm. When combining two together, show columnar liquid crystal (LC) phase structures monomers, including sphere, cylinder, double gyroid, lamella. best our knowledge, this first time gyroid has been achieved copolymers. We further changing side chains to calamitic rod-like) mesogens backbone less flexible polynorbornene, also undergo separation chains. The intrinsic self-assembly scheme mesogenic chains, which are chemically accurate, affords resultant nanostructures precise periodicities at 10- sub-10-nm scale. Given small chemical difference between tails, promoted by anisotropic packing mesogens. It validated LC be versatile platform creating nanostructured materials tailored functionalities.

Язык: Английский

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From Self‐Organization to Tumor‐Immune Therapy: How Things Started and How They Evolved

Macromolecular Rapid Communications, Год журнала: 2022, Номер 43(12)

Опубликована: Июнь 1, 2022

On a sunny afternoon in summer 2021, Rudolf Zentel and Lutz Nuhn visited Helmut Ringsdorf Mainz-Gonsenheim, Germany. It was the first time they were able to meet each other again person after long-lasting restrictions of COVID-19 pandemic. While having cup coffee slice cake on garden terrace, looked back early days "how things started how evolved". In lively discussion participants shared their thoughts naïve ideas from old days, continued, evolved extended lab (Figure 1). These afterwards discussed co-reflected by former students (G. Hörpel, R. Zentel) (M. Barz, L.Nuhn). As result, this perspective article written, which brings together individual opinions authors as — hopefully valuable contribution Macromolecular Rapid Communication's special issue honor upon his retirement. The starting point work polymer science 60s 70s last century (or even better: "the millennium", quotation Ringsdorf). At that time, beginning "plastic era" had just few decades previously, everything related polymers extremely modern, research topic well supported chemical industries. Polymers plastics entered everyday life commodity products made easier postwar era. Especially for people who suffered before many relinquishments, became finally more comfortable. Consequently, gained much popularity throughout society received lot "freedom liberty" explore various non-commercial niches. From today's view, one might claim golden era be origin our current problems plastic waste pollution oceans or soils. is context however, frankly speaking necessary consider these are result being versatile materials: They have been tailored fulfil needs over prolonged very cheap production costs. So, maybe biggest low price guaranteed high benefits industry, but solidified status disposable products. We all know today concepts recycling responsible resource management would necessary, yet, overall enthusiasm superiority may forced aspects step aside. same sciences progressed rapidly series new discoveries leading novel diagnostics therapeutics, revolutionized medicine several fields (e.g., support Rosalind Franklin, James Watson Francis Crick postulated molecular structure DNA 1953, year when Hermann Staudinger awarded with Nobel Prize macromolecular chemistry). A close connection between – nowadays considered two worlds materials still existing, especially head Ringsdorf. light applying daily life, typical topics at i) synthesis (in modern view: rather "simple") monomers ii) detailed study polymerization, including polymerization kinetics potential side reactions thereby obtaining processable materials. Concerning physio–chemical properties, researchers paid further attention characterization viscosity (rheology) solution solid-state properties like crystallinity bulk viscosity. Parallel work, broaden landscape applications: getting order into "plastics" (chemical) functionality make them useful completely areas. And active topics. aspect ordered he searching ways prepare "homogeneously ordered" contrast amorphous partially crystalline materials). it known (at time) partial resulted subsequent crystallization leaves some parts sample non-oriented state, (and others) possibility polymerize an oriented state transfer obtained. But difficult lack mobility) required search types self-organized systems combine mobility.[1] This led attempts liquid state[2] micelles amphiphilic structures.[3] approaches found successful, interest shifted resulting structures.[4, 5] Independent polymers, there growing highly functional enable therapies medical interventions way world wars (especially World War II Cold War). Polymeric plasma expanders studied based poly(vinylpyrrolidone) (PVP) demonstrating ability treating acute injuries heavily wounded soldiers civilians.[6] drug conjugates, Horst Jaskewitz then covalently linked mescalin PVP 1950s observed presence mescaline urine mice.[7, 8] works findings can a) tolerated body b) differ residence since cannot quickly excreted via kidneys small molecules. Based considerations constant threat nuclear apocalypse global powers worked years "long lasting radical scavengers" combat γ-radiation bomb explosions.[9] He explored long-circulating blood stream neutralize ionizing radiation robust strategy helping victims. After diplomatic relaxation following "détente" 1970s, continued applications developed promising concept treatment tumors carrying chemotherapeutics.[10, 11] conceptual 1973 summarized idea conjugating poorly soluble drugs degradable linkers water-soluble equipping structures homing/targeting unit achieve favorable biodistribution 2). For this, multiple efforts requirements polymeric delivery systems, set basis clinical translation galactosamine-modified poly(2-hydroxypropyl methacrylamide) (HPMA)-doxorubicin conjugate (PK2) years.[12] late 80s "polymers tumor therapy"[11, 14] "self-organized systems"[1] LC-phases, lipid layers liposomes 3). Such "order mobility", could nicely addressed systematic route LC-side chain established 1978.[15] later Wüstefeld, et al.[1] Further field also included curious "Wheel Mainz".[4] conjugates[14] (as membrane models)[16] overlapped more. All lines interplay inspired Zentel, beyond measures. scientist, Ringsdorf's greatest think differently, identify encourage different disciplines interdisciplinary question behind remains: How did bring information together? not possible without national international contacts uniquely open personality. take personal understanding too serious. allowed him live "half-knowledge" (quotation H. Ringsdorf) facts, basing decision mostly trusted discussion. addition, "weigh arguments" hierarchical position counterpart, whether well-known professor young student. stressed during discussions group "nearly-no real stupid questions", ideas, sound strange (H. called "Schnappsideen") sometimes turn something great. By such statements, acted typically professor, because often professors liked expert distinct area. thinking, limited investigations only familiar with. "reaction beaker" where associated scientists. "carefully selected". Simply act independently than always looking best grades reputation group. spontaneously organized themselves lives themes "liquid crystals" "lipid membranes".[1, 16] Regarding differentiate strategies attack cancer either "cellular" "molecular" (pharmaceutical) level.[14, 17] lessons learnt stabilizing membranes and, thus, theoretically generating synthetic containers principle artificial cytotoxic cells eliminate analogy immune cells), second focused polymer-drug conjugates access cells, get internalized release inside cell. Thereby, safely administered, interact cell surface, induce endocytosis lysosomal so-called lysosomotropic carrier (according Christian De Duve[18]). Improved design polymer-mediated depot effects (to reduce frequency application) detoxification (while maintaining therapeutic increase selectivity). example, pharmaceutical ingredient (API) cyclophosphamide approved cancers bone marrow (leukemia, "blood cancer"), lymphatic system, breast, ovaries, lungs, bones, central nervous system. However, free caused severe adverse nausea, vomiting, dizziness visual disturbances, possibly circulatory weakness. bad patients, ideal motivation testing model antitumor agents. First, cyclophosphamide-methacrylate copolymerized obtain drug-conjugates. initial loss anticancer activity due conjugation.[19] fortunate Brock al. previously found,[20] studies mechanism action, vivo activated formed microsomal hydroxylases, immediately decomposed de-alkylated derivatives. synthetically accessible oxidation reaction described Peter Hohorst.[21] Following biochemical SH group-containing proteins, spacer molecules synthesized Klesse al[22-25] reacted cyclophosphamide. cleave sulfur bond exert effects. demonstrated cleavage ruled both hydrophobic/hydrophilic balance steric hindrance molecule.[22] words, underline APIs cleavable spacers. validation respect effect realized cooperation labs worldwide. Several conducted National Cancer Institute (NCI) NIH/Bethesda, crosslinking cyclophosphamide-spacer identified successfully. Interestingly showed slightly improved efficacy tumor-bearing mice cyclophosphamide.[26] Back Mainz, encouraging results fixation backbones. To gain chemically, carriers. Beyond used studies,[7, poly(ethylene glycol) (PEG) raised parenterally well-tolerated applications.[27, 28] PEG modifications end groups introduce pharmacologically compounds, functionizable seemed required. respect, already precursor tool flexible matter post-polymerization modifications.[29] Among them, reactive ester chemistry[30] recognized opportunity address reliable conjugation. Poly(methacrylate esters) N-hydroxysuccinimide (NHS), N-hydroxybenzotriazole (HOBt) 2,4,5-trichlorophenol converted polyamides quantitative aminolysis, providing pharmaceutically polymers.[10, 31] Jindřich Kopeček co-workers N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers[32, 33] immunogenicity toxicity.[34, 35] simple strategies. interaction, applied attach drug-spacer esterification. maintain water solubility, conversion 10–15% OH-groups should exceeded. Alternatively, HPMA-doxorubicine most pH-degradable hydrazone chosen.[17, 36] HPMA-based doxorubicine cathepsin-degradable linkers. Successful candidates within 25 enter trials therapies.[37] Primarily comprehensive Ruth Duncan, frequent guest friend family honorary Ph.D. University [38-40] HPMA-doxorubicin PK1[41] becoming passively tumor-targeted prodrug intravenously injected patients 1994.[42] later, PK2[12] actively targeting 2) evaluated primary metastatic liver cancers. pioneer generated better therapeutics biologically complex environment improve therapy.[43] investigated equipped divinyl ether-maleic anhydride (DIVEMA) copolymers, dextrans, imine) (PEI), lower biocompatibility compared PHPMA. Interestingly, drug-polymers higher rate corresponding drug-spacer-conjugates itself. Though, least dextran toxicity thus maximal dose (MTD), worried of, e.g., occur transport through bloodstream moment extended. lipoproteins, self-assembling micellar synthesized, protected core micelles, somehow Trojan horse.[22] using polymers. One containing block copolymer micelle according Figure 4. hydrophilic consists polyethylene oxide, connected hydrophobic poly-L-lysine (PLL). PLL degraded transport, minimize long term effects, e.g. storage diseases.[22] summary, picture emerged: [22] itself markedly toxic agent modified inner no concentrations. Moreover, death curves L1210-tumor bearing striking: contributed significant prolongation despite calculated fraction.[22] Most importantly, PEG-block-poly(amino acids) greatly Kazunori Kataoka 4 evaluation, clearly underlines enormous copolymers relevant translatable nanomedicine.[44-49] note highlight role system colleagues, too.[17] immunoadjuvant methotrexate tumor-associated macrophages,[51, 52] stimulate antigens mimick cancer-specific T-cells considered, polymer-based immunodrug immunotherapy. colleagues nearly 20 initiate collaborative center (CRC/SFB 1066) exploring help nano-sized materials.[53-56] diploma, thesis postdoc Freiburg habilitation lab. diploma November 1978 polymers.[57] During border physics[58] (his jointly co-supervised physicist G. Strobl) structure–property relations systems", crystals, 1985 1989[59, 60] whereby LC-elastomers recently here.[61] selected facet, plays major role, chemists material scientists physico-chemical while challenging find proper biomedical samples. man (compared own scientific "under control" less uncertainties 5). apart selection area research, strongly involved 6) insists "he [Rudolf Zentel] prepared lectures Hütten-Seminars [group seminars]". That stem fact chosen biochemistry additional chemistry studies. Consequently trained "polymer chemistry" thesis, teaching assistant courses science. Later (after 2005, now full "older") type "homecoming" shift initiated department recognition newly monomers,[62] Patrick Theato With biocompatible polymerized well-controlled RAFT talented student, namely Matthias giving defined nano-structured entities (polymer core-crosslinked polymersomes, see 4), here.[13] polypentafluorophenyl (meth)acrylate enabled (block) lauryl methacrylate, easily (multi)functional pHPMA copolymers.[63] pathway avoided finding common solvent amphiphiles characterization, under controlled conditions prevent undesired reactions, hydrolysis.[64] establishment Frank Rösch Insitute Nuclear Chemistry facilitated use positron emission tomography (PET) distribution nanoobjects directly direct feed-back supramolecular distribution.[65, 66] Herth Barz 18F-labeling structure-property relations.[65] link immunology Medical Center Mainz closely focusing target. attraction reasons: cancer-immune therapy requires strong selective activation (that means enough must reached). does require killing drug, will done professional way) body´s system.[52] Secondly, addressable nanostructures another extraordinary student lab, Nuhn.[53, 67] approach utilized generate conjugates. instance, amine-selectivity PFPMA-block install glycopeptides MUC1-derived Kunz, Sebastian Hartmann orthogonally alkyne onto HPMA home copolymers.[68] conjugation T-helper epitopes, vaccines interestingly, methacrylate domains yielded highest antibody titers against MUC1, probably multivalent presentation antigen vaccination. Now, background origins carriers body. experienced simultaneously. Still, quiet move (mostly crystals,[1, 57-60, 69-71] helical polymers[72] opals, [73] see[61] collection). addition German speaker "International Research Training Group" (IRTG 1404) South Korea, dealing OLED materials.[74-76] Nevertheless, activities motivated Katharina Landfester Stephan Grabbe CRC nanomedicine nanoparticle-based Germany (SFB expertise 50% biomedicine nanoparticles effective immunotherapy 6).[53-56] besides willing frame people, continue push forward. Nuhn, serve examples "Ringsdorf-Zentel spirit" shaping independent careers interface science, medicine. postdoctoral stays Maria J. Vicent (Valencia, Spain) Tomas Kirchhausen (Harvard School, Boston, USA) junior 2013. period, polypept(o)ides, (combinations functional/reactive polypeptides polysarcosine).[77, 78] S-alkylsulfonylcysteine -homocysteines applicable peptide classical coupling N-carboxyanhydride polymerization. Afterwards S-alkylsulfonyl protective thiols yielding unsymmetric disulfides chemoselective bioconjugation bioreversible cross-linking chemistry.[79-82] box micelles,[79, 83-85] polymersomes,[86] nanohydrogels polyplexes, [87] nanoparticles,[88] brushes[89-91] organic-inorganic hybrid systems.[89-91] line Zentel's vision every shall designed rational need, Barz's interventions, diagnosis[89] therapy,[92] (immune) therapy[91, 93, 94] bacterial infections.[95-97] polysarcosine[77] hydrophilic, stealth-like substitute PEG[91, 98-100] profile[88, 101]) projects large scale GMP production. researcher continuing level Nuhn. exchange semester Bob Langer ("catalyzed" Ringsdorf),[102] Zentel. development cationic cores.[103] pentafluorophenyl esters undergo self-assembly polar organic solvents.[104] obtained cross-linked aminolysis chemically nanohydrogels. promoted sensitive biomolecules gene modulating siRNA oligonucleotides [55, 105-109] immunostimulatory CpG oligonucleotides.[110] Due accumulation subcutaneous injection, nanohydrogels[111] Bruno Geest (Ghent Unversity, Belgium) attached cues vaccination local immunotherapy.[112-115] surface decoration advanced units nanobodies)[56, 116] repolarized macrophages.[117] joining Tanja Weil's Max Planck Polymer establishing 2019, nanocarriers.[115, 118] backbones[119] alternatively, amine squaric amides provide systemically injectable modulatory (so-called squarogels). [120] Additionally, pH- reductive responsive introduced trigger on-demand degradation precisely.[121, 122] rapid progress sure infrastructure 1066, continuity spirit". Having covered fraction ongoing more), remains what next come. Here, authors, particular honored issue, view future nanomedicines: polymer-science biodegradability materials, currently extensively pollution. seems general prerequisite applications. avoid diseases exposure we do feel (on demand) biodegradable desirable total dependency renal hepatobiliary excretion. aware certain nature nanocarrier surfaces preserved systemic latter affords need alternatives, natural Polysarcosine material, prove its hold true constructed thereof. Micelles, nanohydrogels, formulations stability cargo's protect degradation, premature excretion guarantee efficient ingredients action. fulfilled tasks, nanoparticle fall apart, ideally non-toxic metabolites, disappear. tradition labs, facile (macromolecular) needed requirements. spirit Ringsdorf-Zentel therefore contribute generation nanosized equally work. gratefully thank kindly sharing memories historic manifold advice years. M.B., L.N. R.Z. Foundation (DFG) generous financial Collaborative SFB 1066. declare conflict interest. Johannes Gutenberg-University (Germany) 1983 Profs. Strobl. stay (Germany), "IBM Almaden Center" San Jose (USA, 1989–1990) Düsseldorf (Germany, 1990–1992) got professorship 1992. Wuppertal 1996 2000) came 2000. There successively Group, IRTG (2006 2015) (SFB) 1066 (2013 periods), funded DFG. retired countless achievements

Язык: Английский

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Main-chain side-chain combined liquid crystalline polymers bearing azobenzene and biphenyl-based mesogens – segregation of the mesogens within two distinct layers

Liquid Crystals, Год журнала: 2022, Номер 49(7-9), С. 1020 - 1030

Опубликована: Март 23, 2022

Two different mesogenic units, namely biphenyl and azobenzene, were installed centrally within the polymer backbone pendant alkylene segments; purpose was to examine if chain folding of occurs so as segregate azobenzene units in adjacent layers a smectic-type ordering. sets isomeric main-chain side-chain liquid crystalline polymers (MCSC-LCPs), SC-AzoCx-MC-BPCx SC-BPCx-MC-AzoCx (x=6 or 10), synthesised; former series has side-chain, while their locations are switched latter. It observed that all four semicrystalline at room temperature exhibited smectic mesophase upon melting. DSC X-ray scattering studies revealed switching biphenyls had little effect on; phase transition temperatures layer spacings. A second series, SC-AzoCx-MC-BPCy SC-BPCx-MC-AzoCy, where length spacers (Cx) (Cy) is different, also studied; this done influence unequal segment lengths on structure interlayer spacing, importantly, whether zigzag folding-induced formation layered retained, despite unsymmetrical nature.

Язык: Английский

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