Supramolecular crosslinking of biomimetic poly(2-hydroxyethyl methacrylate) nanocomposite reinforced with multi-walled carbon nanotubes

Evolving technology sets new requirements to material development all the time. Many scientists are trying to meet these requirements by the means of biomimetics. Biomaterials, like spider silk and nacre, have exceptional properties which derive from their hierarchical organization and supramolecular interactions. Spider silk has attracted plenty of attention during the past decades. It has high tensile strength and very good elongation properties but in addition to these, researchers are interested in of the energy dissipating properties which arise from sacrificial bonding and hidden lengths in the protein structure. Production of synthetic spider silk has been approached in several ways. Different nanocomposites consisting of polymers and carbon nanotubes have been studied extensively. In these nanocomposites, carbon nanotubes are used to mimic reinforcing β-sheets which enable high tensile strength of spider silk. Polymer is used to simulate the non-crystalline regions which give rise to high elongation of spider silk. In this Master's thesis, a review of supramolecular concepts enabling biomimetic research is presented. Also chemical and physical structure and properties of spider silk and carbon nanotubes and their role in different biomimetic materials are presented. The experimental part of this thesis consists of functionalization of multi-walled carbon nanotubes and poly(2-hydroxyethyl methacrylate) with 2-ureido-4[1H]-pyrimidinone hexamethylene isocyanate. These materials were used to prepare nanocomposites via self-assembly. The aim of this study was to prepare two-component nanocomposite with high tensile strength. Tensile tests on the nanocomposites were carried out and major improvement in the mechanical properties were observed. Even though the ultimate strength of the materials did not reach expected values, the composites functionalized with dimerizing ureidopyrimidinone-motifs resisted crack growth like predicted

Molecular crowding facilitates assembly of spidroin-like proteins through phase separation

Gaining insights into the processes that transform dispersed biopolymers into well-ordered structures, such as soluble spidroin-proteins to spider silk threads, is essential for attempts to understand their biological function and to mimic their unique properties. One of these processes is liquid-liquid phase separation, which can act as an intermediate step for molecular assembly. We have shown that a self-coacervation step that occurs at a very high protein concentration (> 200 gl(-1)) is crucial for the fiber assembly of an engineered triblock silk-like molecule. In this study, we demonstrate that the addition of a crowding agent lowers the concentration at which coacervation occurs by almost two orders of magnitude. Coacervates induced by addition of a crowding agent are functional in terms of fiber formation, and the crowding agent appears to affect the process solely by increasing the effective concentration of the protein. Furthermore, induction at lower concentrations allows us to study the thermodynamics of the system, which provides insights into the coacervation mechanism. We suggest that this approach will be valuable for studies of biological coacervating systems in general.Peer reviewe

WtF-Nano : One-Pot Dewatering and Water-Free Topochemical Modification of Nanocellulose in Ionic Liquids or gamma-Valerolactone

Ionic liquids are used to dewater a suspension of birch Kraft pulp cellulose nanofibrils (CNF) and as a medium for water-free topochemical modification of the nanocellulose (a process denoted as "WtF-Nano"). Acetylation was applied as a model reaction to investigate the degree of modification and scope of effective ionic liquid structures. Little difference in reactivity was observed when water was removed, after introduction of an ionic liquid or molecular co-solvent. However, the viscoelastic properties of the CNF suspended in two ionic liquids show that the more basic, but non-dissolving ionic liquid, allows for better solvation of the CNF. Vibrio fischeri bacterial tests show that all ionic liquids in this study were harmless. Scanning electron microscopy and wide-angle X-ray scattering on regenerated samples show that the acetylated CNF is still in a fibrillar form. 1D and 2D NMR analyses, after direct dissolution in a novel ionic liquid electrolyte solution, indicate that both cellulose and residual xylan on the surface of the nanofibrils reacts to give acetate esters.Peer reviewe

Molekulaariset järjestäytymisreitit biologisissa materiaaleissa

Biological materials present a wide variety of functional properties that provide inspiration for the development of new synthetic biomaterials. For example, spider silk has been extensively studied due to its exceptional toughness and adhesion properties. The exact pathway leading to the correct molecular assembly, which is the foundation of its extraordinary mechanical properties, is a complex process and not fully understood. This is one of the main reasons why the properties of synthetic silk materials are inferior to natural ones. This thesis attempts to answer the question of how recombinant spider silk proteins can be brought together in soluble form in a way that enables the interactions and microstructures that yield strong materials. The possible role of liquid-liquid phase separation, also known as coacervation, in the correct molecular assembly is of special interest. It has been suggested that many other natural organisms utilize coacervation as an intermediate step to produce functional materials, so gaining more information about its role on molecular assembly would be of great value to materials science. In publication I the coacervation of a recombinant spider silk-like protein, CBM-eADF3-CBM, was studied as an intermediate step for fiber assembly. Depending on the conditions, two kinds of coacervates were obtained: liquid-like and solid-like coacervates, but only the liquid-like ones enabled fiber formation and thus were more interesting for further studies. Publication II focused on the effect of molecular crowding on coacervation of CBM-eADF3-CBM. Dextran was used as an inert crowding agent, which enabled studying phase separation in lower protein concentrations, and in a controlled set-up. Furthermore, this set-up enabled thermodynamic studies of the system, which provided insight into the coacervation mechanism. Publication III presents the adhesion properties of CBM-eADF3-CBM in a system with delignified cellulose. Delignified cellulose proved to be a well-functioning model system to study silk as an adhesive, and CBM-eADF3-CBM formed a strong adhesive system with it. A method to produce native-sized recombinant silk proteins was developed in publication IV, and the effect of protein length on coacervation was studied. Post-translational in vitro ligation with the SpyCatcher2-SpyTag protein-peptide pair proved to be a robust way to produce native-sized silk proteins with high yield and solubility. Lengthening the protein lowered the critical concentration needed for coacervation and provided insight into the molecular interactions that lead to phase separation. To conclude, the results show that engineered recombinant silk proteins can be used to gain a deeper understanding of the molecular assembly behind the material formation process. Coacervation proved to be an important step in material formation and the methods to study it developed in this thesis increased the knowledge of molecular assembly processes.Biologiset materiaalit tarjoavat laajan valikoiman toiminnallisia ominaisuuksia, jotka inspiroivat uusien synteettisten biomateriaalien kehitystä. Esimerkiksi hämähäkin silkkiä on tutkittu laajasti sen poikkeuksellisten mekaanisten ja adheesio-ominaisuuksien vuoksi. Välivaiheet, jotka johtavat molekyylien oikeaan järjestäytymiseen, ja jotka ovat hämähäkin silkin erinomaisten mekaanisten ominaisuuksien perusta, ovat monimutkaisia, eikä niitä vielä ymmärretä kunnolla. Tämä on yksi suurimmista syistä, jonka takia synteettiset silkkimateriaalit ovat ominaisuuksiltaan huonompia kuin luonnolliset materiaalit. Tämä väitöskirja pyrkii vastaamaan siihen, miten saamme tuotua rekombinanttiset hämähäkin silkkiproteiinit yhteen liukoisessa muodossa niin, että ne voivat muodostaa vahvojen materiaalien edellyttämät vuorovaikutukset ja mikrorakenteet. Neste-neste faasierottumisen (koaservoitumisen) rooli molekyylien järjestäytymiselle on erityisen kiinnostava. Useiden luonnon organismien uskotaan käyttävän koaservaatiota välivaiheena toiminnallisten materiaalien tuottamisessa. Siksi materiaalitieteelle olisi erittäin tärkeää, että sen rooli molekyylien järjestäytymiselle ymmärrettäisi paremmin. Julkaisussa I tutkittiin rekombinanttisen silkinkaltaisen proteiinin, CBM-eADF3-CBM, koaservaatiota välivaiheena kuitujen muodostumiselle. Olosuhteita muuttamalla saatiin aikaan kahdenlaisia koaservaatteja: nestemäisiä ja kiinteitä. Nestemäiset koaservaatit mahdollistivat kuitujen vedon ollen siksi kiinnostavampia lisätutkimuksille. Julkaisussa II tutkittiin molekulaarisen pakkaamisen (crowding) vaikutusta CBM-eADF3-CBM:n koaservaatiolle. Dekstraania käytettiin inerttinä pakkausaineena ja se mahdollisti faasierottumisen tutkimisen matalammassa konsentraatiossa ja kontrolloidussa systeemissä. Dekstraani mahdollisti myös koaservaation termodynamiikan tutkimisen, mistä saimme lisätietoa koaservaation mekanismista. Julkaisu III esittää CBM-eADF3-CBM:n ahdeesio-ominaisuudet delignifioidun selluloosan kanssa. Delignifioitu selluloosa osoittautui hyväksi mallisysteemiksi adheesion tutkimiselle ja CBM-eADF3-CBM muodosti vahvan adheesion sen kanssa. Julkaisussa IV kehitettiin metodi luonnollisen kokoisten silkkiproteiinien tuottamiseksi ja tutkittiin proteiinin pituuden vaikutusta koaservaatioon. Translaation jälkeinen in vitro -ligaatio SpyCatcher2-SpyTag proteiini-peptidi -parin avulla osoittautui tehokkaaksi tavaksi tuottaa luonnollisen kokoisia silkkiproteiineja. Proteiinin pidentäminen alensi koaservaation vaatimaa kriittistä konsentraatiota ja lisäsi tietämystämme faasierottumiseen johtavasta molekyylien järjestäytymisestä. Yhteenvetona tulokset osoittavat, että rekombinanttisia silkkiproteiineja voidaan käyttää materiaalien muodostumiseen johtavan molekyylien järjestäytymisen ymmärtämiseen. Koaservaatio osoittautui tärkeäksi välivaiheeksi materiaalin muodostumiselle ja tässä väitöskirjassa kehitetyt tutkimusmetodit lisäsivät tietoa molekyylien järjestäytymisprosesseista

Study of Work Environment and Recommendations for Improvements for Welders when Welding in Copper : ABB Transformers Plate Shop

Examensarbetet har utförts vid ABB Power Transformers i Ludvika i plåtverkstaden, där stora transformatorlådor svetsas ihop. Tillsammans med vår handledare på företaget utformades ämnet för examensarbetet att bedöma luftkvalitet och arbetsmiljö vid punktsvetsning i koppar. Det fanns misstanke om att exponeringen för koppar var hög och en utvärdering av luftkvaliteten behövde därmed göras. Ingen tidigare exponeringsmätning vid svetsning i koppar har genomförts i plåtverkstaden.   Syftet med examensarbetet var att utvärdera och komma fram till tre åtgärdsförslag för att skapa en bättre arbetsmiljö vid punktsvetsning samt att begränsa exponeringen av svetsrök som bildas vid svetsning i koppar. Tre åtgärder var företagets önskemål. En exponeringsmätning av luftföroreningar vid svetsning i koppar gjordes för att kontrollera halten av ämnen i svetsröken, i förhållande till de hygieniska nivågränsvärdena. Exponeringsmätningen gjordes personburet. Dessutom gjordes stationär mätning samt mätning med direktvisande instrument. Användning av skyddsutrustning och ventilationen granskades. I samband med exponeringsmätning genomfördes intervjuer.   Resultatet av exponeringsmätningarna har visat att det hygieniska nivågränsvärdet för koppar överstegs kraftigt vid punktsvetsning med MIGsvetsmetoden. Nivågränsvärdet för koppar är 0,2 mg/m3 och det högsta uppmätta värdet uppgick till 1,05 mg/m3, mätt utanför svetsvisiret. Utifrån observationer om användning av skyddsutrustning har det noterats att det finns tillgång till lämplig skyddsutrustning men att den inte används i den utsträckning som den borde. De tre åtgärdsförslag vi utvecklade är att; (1) införa rutiner för filterbyte med jämna mellanrum, (2) börja använda integrerade utsug i större utsträckning samt att (3) förbättra lokalens ventilation genom att installera deplacerande ventilation. De två beräknade åtgärdskostnaderna, åtgärd (1) och (2), följer företagets PayOff-princip på 3 år.   Examensarbetet ska bidra till att alla medarbetare i plåtverkstaden blir medvetna om de risker som exponering av svetsrök innebär, men även att de tänker på sin egen och andras säkerhet och hälsa i deras dagliga arbete samt vidtar åtgärder som effektivt minskar exponeringen av svetsrök. Att satsa på en bra arbetsmiljö innebär kostnader för exempelvis inköp av skyddsutrustning och utbildning om risker. Detta bör dock inte ses som en kostnad utan att det snarare är en investering på sikt, som förbättrar medarbetares hälsa och prestationsförmåga i arbetet. Avslutningsvis: Att satsa på en bra fysisk och psykosocial arbetsmiljö är en investering för att få ett väl fungerande och lönsamt företag!This thesis has been carried out at ABB Power Transformers in Ludvika at the plate shop, where large transformer boxes are welded together. The topic of the thesis was formulated together with our supervisor at the company, to assess air quality and work environment at the spot welding of copper. Copper exposure was suspected to be high, and an evaluation of air quality was needed. No previous exposure measurements when welding in copper have been made in the plate shop.   The purpose of this study was to evaluate and come up with three proposals for actions to create a better working environment for spot welding as well as to limit exposure to welding fumes generated during welding of copper. An exposure measurement of air pollutants during welding of copper was done to evaluate copper exposure compared to threshold limit values of substances in welding fume. Exposure measurements were made with personal monitors. In addition, measurement with stationary equipment and measurement with directreading instruments. The use of protective equipment and ventilation were studied. In connection with measurements interviews were made.   The results of exposure measurements showed that the occupational exposure limit value for copper was exceeded considerably during the spot welding with the MIG welding process. The threshold limit value of copper is 0,2 mg/m3 and the highest value measured was 1,05 mg/m3, measured outside the welding shield. Based on observations on the use of personal protective equipment it has been noted that protective equipment is available but not used to desired extent. Three control actions are proposed; (1) routines to change the respiratory protective equipment filter regularly, (2) start using local exhaust integrated in the welding gun to a greater extent and (3) improve the ventilation in the plate shop by installing displacement ventilation. The calculated costs for two of the actions, action (1) and (2), fulfill the company's payoff principle of 3 years.   The thesis will contribute to making all employees in the plate shop aware of the risks that the work involves exposure to welding fumes. But even that they think of their own and others' safety and health in their daily work and adopt measures that effectively reduce exposure to welding fumes. To invest in a good working environment involves costs, such as protective and risk education. However, this should not be viewed as a cost but rather that it is an investment in the long run, that improve employee health and performance at work. In conclusion: To invest in a good physical and psychosocial work environment is an investment to get an efficient and profitable business

Study of Work Environment and Recommendations for Improvements for Welders when Welding in Copper : ABB Transformers Plate Shop

Examensarbetet har utförts vid ABB Power Transformers i Ludvika i plåtverkstaden, där stora transformatorlådor svetsas ihop. Tillsammans med vår handledare på företaget utformades ämnet för examensarbetet att bedöma luftkvalitet och arbetsmiljö vid punktsvetsning i koppar. Det fanns misstanke om att exponeringen för koppar var hög och en utvärdering av luftkvaliteten behövde därmed göras. Ingen tidigare exponeringsmätning vid svetsning i koppar har genomförts i plåtverkstaden.   Syftet med examensarbetet var att utvärdera och komma fram till tre åtgärdsförslag för att skapa en bättre arbetsmiljö vid punktsvetsning samt att begränsa exponeringen av svetsrök som bildas vid svetsning i koppar. Tre åtgärder var företagets önskemål. En exponeringsmätning av luftföroreningar vid svetsning i koppar gjordes för att kontrollera halten av ämnen i svetsröken, i förhållande till de hygieniska nivågränsvärdena. Exponeringsmätningen gjordes personburet. Dessutom gjordes stationär mätning samt mätning med direktvisande instrument. Användning av skyddsutrustning och ventilationen granskades. I samband med exponeringsmätning genomfördes intervjuer.   Resultatet av exponeringsmätningarna har visat att det hygieniska nivågränsvärdet för koppar överstegs kraftigt vid punktsvetsning med MIGsvetsmetoden. Nivågränsvärdet för koppar är 0,2 mg/m3 och det högsta uppmätta värdet uppgick till 1,05 mg/m3, mätt utanför svetsvisiret. Utifrån observationer om användning av skyddsutrustning har det noterats att det finns tillgång till lämplig skyddsutrustning men att den inte används i den utsträckning som den borde. De tre åtgärdsförslag vi utvecklade är att; (1) införa rutiner för filterbyte med jämna mellanrum, (2) börja använda integrerade utsug i större utsträckning samt att (3) förbättra lokalens ventilation genom att installera deplacerande ventilation. De två beräknade åtgärdskostnaderna, åtgärd (1) och (2), följer företagets PayOff-princip på 3 år.   Examensarbetet ska bidra till att alla medarbetare i plåtverkstaden blir medvetna om de risker som exponering av svetsrök innebär, men även att de tänker på sin egen och andras säkerhet och hälsa i deras dagliga arbete samt vidtar åtgärder som effektivt minskar exponeringen av svetsrök. Att satsa på en bra arbetsmiljö innebär kostnader för exempelvis inköp av skyddsutrustning och utbildning om risker. Detta bör dock inte ses som en kostnad utan att det snarare är en investering på sikt, som förbättrar medarbetares hälsa och prestationsförmåga i arbetet. Avslutningsvis: Att satsa på en bra fysisk och psykosocial arbetsmiljö är en investering för att få ett väl fungerande och lönsamt företag!This thesis has been carried out at ABB Power Transformers in Ludvika at the plate shop, where large transformer boxes are welded together. The topic of the thesis was formulated together with our supervisor at the company, to assess air quality and work environment at the spot welding of copper. Copper exposure was suspected to be high, and an evaluation of air quality was needed. No previous exposure measurements when welding in copper have been made in the plate shop.   The purpose of this study was to evaluate and come up with three proposals for actions to create a better working environment for spot welding as well as to limit exposure to welding fumes generated during welding of copper. An exposure measurement of air pollutants during welding of copper was done to evaluate copper exposure compared to threshold limit values of substances in welding fume. Exposure measurements were made with personal monitors. In addition, measurement with stationary equipment and measurement with directreading instruments. The use of protective equipment and ventilation were studied. In connection with measurements interviews were made.   The results of exposure measurements showed that the occupational exposure limit value for copper was exceeded considerably during the spot welding with the MIG welding process. The threshold limit value of copper is 0,2 mg/m3 and the highest value measured was 1,05 mg/m3, measured outside the welding shield. Based on observations on the use of personal protective equipment it has been noted that protective equipment is available but not used to desired extent. Three control actions are proposed; (1) routines to change the respiratory protective equipment filter regularly, (2) start using local exhaust integrated in the welding gun to a greater extent and (3) improve the ventilation in the plate shop by installing displacement ventilation. The calculated costs for two of the actions, action (1) and (2), fulfill the company's payoff principle of 3 years.   The thesis will contribute to making all employees in the plate shop aware of the risks that the work involves exposure to welding fumes. But even that they think of their own and others' safety and health in their daily work and adopt measures that effectively reduce exposure to welding fumes. To invest in a good working environment involves costs, such as protective and risk education. However, this should not be viewed as a cost but rather that it is an investment in the long run, that improve employee health and performance at work. In conclusion: To invest in a good physical and psychosocial work environment is an investment to get an efficient and profitable business

Hierarchical Supramolecular Cross-Linking of Polymers for Biomimetic Fracture Energy Dissipating Sacrificial Bonds and Defect Tolerance under Mechanical Loading

| openaire: EC/FP7/291364/EU//MIMEFUNBiological structural materials offer fascinating models how to synergistically increase the solid-state defect tolerance, toughness, and strength using nanocomposite structures by incorporating different levels of supramolecular sacrificial bonds to dissipate fracture energy. Inspired thereof, we show how to turn a commodity acrylate polymer, characteristically showing a brittle solid state fracture, to become defect tolerant manifesting noncatastrophic crack propagation by incorporation of different levels of fracture energy dissipating supramolecular interactions. Therein, poly(2-hydroxyethyl methacrylate) (pHEMA) is a feasible model polymer showing brittle solid state fracture in spite of a high maximum strain and clear yielding, where the weak hydroxyl group mediated hydrogen bonds do not suffice to dissipate fracture energy. We provide the next level stronger supramolecular interactions toward solid-state networks by postfunctionalizing a minor part of the HEMA repeat units using 2-ureido-4[1H]-pyrimidinone (UPy), capable of forming four strong parallel hydrogen bonds. Interestingly, such a polymer, denoted here as p(HEMA-co-UPyMA), shows toughening by suppressed catastrophic crack propagation, even if the strength and stiffness are synergistically increased. At the still higher hierarchical level, colloidal level cross-linking using oxidized carbon nanotubes with hydrogen bonding surface decorations, including UPy, COOH, and OH groups, leads to further increased stiffness and ultimate strength, still leading to suppressed catastrophic crack propagation. The findings suggest to incorporate a hierarchy of supramolecular groups of different interactions strengths upon pursuing toward biomimetic toughening.Peer reviewe

Recombinant Spider Silk Protein and Delignified Wood Form a Strong Adhesive System

Funding Information: This work was performed within the project “Strong Composite” supported under the umbrella of ERANET Cofund ForestValue, funded by Academy of Finland projects #308772, #317395, #326345, and #333238. The authors are grateful for the support by the FinnCERES Materials Bioeconomy Ecosystem, the Bioeconomy Infrastructure, and the OtaNano─Nanomicroscopy Center (Aalto-NMC) at Aalto University. Publisher Copyright: © 2021 The Authors. Published by American Chemical Society.For developing novel fully biological materials, a central question is how we can utilize natural components in combination with biomimetic strategies in ways that both allow feasible processing and high performance. Within this development, adhesives play a central role. Here, we have combined two of nature's excellent materials, silk and cellulose, to function as an adhesive system. As an initial step in processing, wood was delignified. Without lignin, the essential microstructure and alignment of the wood remain, giving a strong scaffold that is versatile to process further. A recombinant spider silk protein was used as a fully biological and water-based adhesive. The adhesive strength was excellent with an average value of 6.7 MPa, with a maximum value of up to 10 MPa. Samples of different strengths showed characteristic features, with high tear-outs for weaker samples and only little tear-out for strong samples. As references, bovine serum albumin and starch were used. Based on the combined data, we propose an overall model for the system and highlight how multiple variables affect performance. Adhesives, in particular, biobased ones, must be developed to be compatible with the overall adherend system for suitable infiltration and so that their mechanical properties match the adherend. The engineering of proteins gives an unmatched potential for designing adhesive systems that additionally have desired properties such as being fully water-based, biologically produced, and renewable.Peer reviewe

Self-assembly of silk-like protein into nanoscale bicontinuous networks under phase separation conditions

Liquid–liquid phase separation of biomacromolecules is crucial in various inter- and extracellular biological functions. This includes formation of condensates to control, e.g., biochemical reactions and structural assembly. The same phenomenon is also found to be critically important in protein-based high-performance biological materials. Here, we use a well-characterized model triblock protein system to demonstrate the molecular level formation mechanism and structure of its condensate. Large-scale molecular modeling supported by analytical ultracentrifuge characterization combined with our earlier high magnification precision cryo-SEM microscopy imaging leads to deducing that the condensate has a bicontinuous network structure. The bicontinuous network rises from the proteins having a combination of sites with stronger mutual attraction and multiple weakly attractive regions connected by flexible, multiconfigurational linker regions. These attractive sites and regions behave as stickers of varying adhesionstrength. For the examined model triblock protein construct, the β-sheet-rich end units are the stronger stickers, while additional weaker stickers, contributing to the condensation affinity, rise from spring-like connections in the flexible middle region of the protein. The combination of stronger and weaker sticker-like connections and the flexible regions between the stickers result in a versatile, liquid-like, self-healing structure. This structure also explains the high flexibility, easy deformability, and diffusion of the proteins, decreasing only 10–100 times in the bicontinuous network formed in the condensate phase in comparison to dilute protein solution. The here demonstrated structure and condensation mechanism of a model triblock protein construct via a combination of the stronger binding regions and the weaker, flexible sacrificial-bond-like network as well as its generalizability via polymer sticker models provide means to not only understand intracellular organization, regulation, and cellular function but also to identify direct control factors for and to enable engineering improved protein and polymer constructs to enhance control of advanced fiber materials, smart liquid biointerfaces, or self-healing matrices for pharmaceutics or bioengineering materials.Peer reviewe

Hierarchical Supramolecular Cross-Linking of Polymers for Biomimetic Fracture Energy Dissipating Sacrificial Bonds and Defect Tolerance under Mechanical Loading

Biological structural materials offer fascinating models how to synergistically increase the solid-state defect tolerance, toughness, and strength using nanocomposite structures by incorporating different levels of supramolecular sacrificial bonds to dissipate fracture energy. Inspired thereof, we show how to turn a commodity acrylate polymer, characteristically showing a brittle solid state fracture, to become defect tolerant manifesting noncatastrophic crack propagation by incorporation of different levels of fracture energy dissipating supramolecular interactions. Therein, poly­(2-hydroxyethyl methacrylate) (pHEMA) is a feasible model polymer showing brittle solid state fracture in spite of a high maximum strain and clear yielding, where the weak hydroxyl group mediated hydrogen bonds do not suffice to dissipate fracture energy. We provide the next level stronger supramolecular interactions toward solid-state networks by postfunctionalizing a minor part of the HEMA repeat units using 2-ureido-4­[1<i>H</i>]-pyrimidinone (UPy), capable of forming four strong parallel hydrogen bonds. Interestingly, such a polymer, denoted here as p­(HEMA-<i>co</i>-UPyMA), shows toughening by suppressed catastrophic crack propagation, even if the strength and stiffness are synergistically increased. At the still higher hierarchical level, colloidal level cross-linking using oxidized carbon nanotubes with hydrogen bonding surface decorations, including UPy, COOH, and OH groups, leads to further increased stiffness and ultimate strength, still leading to suppressed catastrophic crack propagation. The findings suggest to incorporate a hierarchy of supramolecular groups of different interactions strengths upon pursuing toward biomimetic toughening