26 results on '"Joost Duvigneau"'
Search Results
2. Polydopamine as a Materials Platform to Promote Strong and Durable Interfaces in Thermoplastic Polymer‐Titanium Joints
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Georgios Kafkopoulos, Joost Duvigneau, and G. Julius Vancso
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interfacial adhesion ,PDA thermal annealing ,polydopamine ,thermoplastic polymer‐metal bonding ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Abstract Joining thermoplastic polymers (TPMs) and metals to form lightweight hybrid structures is of growing industrial and commercial importance. The performance of such materials relies on the bonding strength and endurance of the formed TPM–metal interfaces. The available joining technologies and the mechanisms that govern interfacial adhesion are reviewed in this contribution, highlighting thermal bonding as a commercially attractive joining method. By focusing on molecular interactions to optimize interfacial adhesion, the use of dopamine as a building block to form polydopamine (PDA) based adhesive interlayers in such interfaces is discussed. This work also highlights the potential of PDA to be applied as a load‐bearing adhesive—a notion considered to date unfeasible.
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- 2024
- Full Text
- View/download PDF
3. Designer Adhesives for Tough and Durable Interfaces in High‐Performance Ti‐Carbon PEKK Hybrid Joints
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Georgios Kafkopoulos, Vanessa M. Marinosci, Joost Duvigneau, Wouter J. B. Grouve, Sebastiaan Wijskamp, Matthijn B. deRooij, G. Julius Vancso, and Remko Akkerman
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adhesive bonding ,APTES ,C/PEKK ,hot/wet conditioning resistance ,polydopamine ,polymer‐metal joint ,Physics ,QC1-999 ,Technology - Abstract
Abstract Advanced high‐performance structural applications require the right materials in the right place and suitable interface engineering. However, poor adhesion in harsh environmental conditions frequently challenge material interfaces. An example is the moisture sensitivity of titanium‐poly ether ketone ketone (PEKK) interfaces. Here, this work offers a high‐performance composite adhesive system, which combines strong adhesion and high interfacial toughness, particularly when used in metal‐polymer bonding. This system includes aminopropyl triethoxy silane (APTES)–polydopamine (SiPDA) layers, which can be formed on the titanium surface before the joining process with carbon fiber‐reinforced PEKK (C/PEKK). Adhesion between PEKK and titanium is evaluated before and after hot/wet conditioning using mandrel peel tests. This work discovers that applying thin SiPDA layers not only results in a remarkable rise in the interfacial fracture toughness but also provides durable bond stability after hot/wet conditioning. These findings indicate that polydopamine‐based coatings show great potential to achieve stable interfaces for the next generation of high‐performance metal‐polymer hybrid materials.
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- 2023
- Full Text
- View/download PDF
4. Foaming of Polylactic Acid/Cellulose Nanocrystal Composites: Pickering Emulsion Templating for High-Homogeneity Filler Dispersions
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Yunchong Zhang, Joost Duvigneau, Xiaofeng Sui, G. Julius Vancso, Sustainable Polymer Chemistry, MESA+ Institute, and Materials Science and Technology of Polymers
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Polymers and Plastics ,Pickering emulsion ,Masterbatch ,Process Chemistry and Technology ,Organic Chemistry ,UT-Hybrid-D ,Polylactic acid (PLA) ,Dispersion ,Foaming ,Cellulose nanocrystal - Abstract
Polylactic acid (PLA)/cellulose nanocrystal (CNC) composite foams have attracted much attention due to their biodegradability and potential to replace petroleum-based foams. However, the dispersion of (unmodified) CNCs in PLA remains challenging. Here, we used the Pickering emulsion templating method of unmodified CNCs to stabilize PLA microspheres and prepare a concentrated masterbatch. This masterbatch was used in conventional melt blending of pristine PLA to obtain well-dispersed CNCs in PLA with a CNC loading of up to 5 wt %. In comparison, PLA/CNC composites prepared by direct melt blending of CNCs in PLA showed visual agglomerates of CNCs. PLA/CNC composites were batch foamed with CO2 as a physical blowing agent. We demonstrate that the good CNC dispersion obtained by the Pickering emulsion route is favorable for preparing PLA foams with smaller and more uniform cell sizes and with a higher cell density. These results demonstrate that the Pickering emulsion approach to prepare CNC masterbatches for subsequent dispersion in thermoplastics by conventional processing seems promising for numerous industrial applications.
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- 2021
5. Fluorescent Polyethylene by in Situ Facile Synthesis of Carbon Quantum Dots Facilitated by Silica Nanoparticle Agglomerates
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Sida Yin, Joost Duvigneau, G. Julius Vancso, Sustainable Polymer Chemistry, and MESA+ Institute
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In situ ,Materials science ,Polymers and Plastics ,Process Chemistry and Technology ,Organic Chemistry ,UT-Hybrid-D ,Polyethylene ,Polyethylene (PE) ,Fluorescence ,Silica nanoparticles ,Plastic sorting ,Carbon quantum dots ,chemistry.chemical_compound ,Optical markers ,chemistry ,Chemical engineering ,Agglomerate - Abstract
We describe an in situ facile synthetic approach to prepare carbon quantum dot (CQD) fluorescent markers (FMs) for polyethylene (PE) in the presence of agglomerated silica nanoparticles (SiO2 NPs) under mild reaction conditions. First SiO2 NPs, prepared by the Stöber method, were dispersed in toluene. This dispersion was added to a PE solution in toluene. After heating (either in air or under Ar) a fluorescent mixture was obtained. After drying, PE films were obtained by compression molding, which showed strong blue fluorescence, attributed to CQDs. SiO2 NPs loading values varied between 0.5 and 4 wt %. Subsequent to isolation, the fluorescent CQDs were characterized by TEM, UV-vis, and fluorescence spectroscopy. TEM imaging unveiled a lattice spacing value of 0.21 nm of the isolated fluorescent particles which is typical for (100) graphite plane lattice spacing in CQDs. UV spectroscopy and fluorescence measurements show characteristic absorption and excitation spectra for the aromatic core and oxidized surface defects typically observed for CQDs. The emission maximum for PE/CQD samples increased from 394 to 408 nm when the reaction temperature was decreased from 110 to 90 °C, which is attributed to increasing oxygen content in the reaction mixture upon decreasing the reaction temperature. When the reaction was performed under Ar, the PE/CQD samples emitted in the ultraviolet region (286 nm). Finally, we demonstrated that PE samples marked with CQDs can be easily visually identified upon irradiating with 367 nm light. Thus, the marked PE can be used, for example, as a labeling ingredient in master batches for component identification and in recycling.
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- 2021
6. Polydopamine as Adhesion Promotor
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Georgios Kafkopoulos, Ezgi Karakurt, Joost Duvigneau, G. Julius Vancso, MESA+ Institute, Sustainable Polymer Chemistry, and Materials Science and Technology of Polymers
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Titanium ,Polydopamine ,Polymers and Plastics ,Organic Chemistry ,Poly(lactic acid) ,Materials Chemistry ,UT-Hybrid-D ,Interface ,Condensed Matter Physics ,Polymer-metal adhesion ,Stainless steel - Abstract
Molecular interactions in polymer/metal oxide interfaces are of paramount interest in polymer composite applications, including comolding of polymer-metal joints, additive manufacturing, and mold release. This study shows the potential of biomimetic polydopamine (PDA) layers to control polymer-metal adhesion covering a range from strong bonding to release for poly(lactic acid) (PLA) adhering to two metals of significant commercial importance, i.e., titanium (Ti) and stainless steel (SS). The results show that even though PLA bonds significantly weaker to Ti than to SS surfaces, both metals exhibit considerably higher and similar adhesion values following deposition of a PDA layer. In addition, a simple thermal annealing of the PDA-coated wires before the comolding process results in a sharp increase of the bonding strength at low annealing temperatures, followed by a gradual drop at higher annealing temperatures. This observation opens the possibility to provide control of adhesion in polymer-metal interfaces. As PDA forms strongly bound adhesive layers on a wide range of materials, this study proposes that the phenomenon described here can be successfully applied to surfaces other than metals, raising high expectations for future polymer composite applications.
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- 2022
7. Designer Core–Shell Nanoparticles as Polymer Foam Cell Nucleating Agents: The Impact of Molecularly Engineered Interfaces
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Kevin M. Batenburg, Sissi de Beer, G. Julius Vancso, Joost Duvigneau, Shanqiu Liu, Hubert Gojzewski, Materials Science and Technology of Polymers, MESA+ Institute, and Sustainable Polymer Chemistry
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Thermogravimetric analysis ,Materials science ,Scanning electron microscope ,Interface compatibility ,UT-Hybrid-D ,Nucleation ,Nanoparticle ,Designer core-shell nanoparticles ,02 engineering and technology ,Gas-partitioning ,010402 general chemistry ,01 natural sciences ,designer core−shell nanoparticles ,chemistry.chemical_compound ,COaccumulation ,General Materials Science ,Fourier transform infrared spectroscopy ,chemistry.chemical_classification ,CO2 accumulation ,Molecular dynamics simulations ,technology, industry, and agriculture ,Polymer ,021001 nanoscience & nanotechnology ,Microcellular and nanocellular foams ,0104 chemical sciences ,Foam cell nucleation ,chemistry ,Chemical engineering ,Particle ,Polystyrene ,0210 nano-technology ,Research Article - Abstract
The interface between nucleating agents and polymers plays a pivotal role in heterogeneous cell nucleation in polymer foaming. We describe how interfacial engineering of nucleating particles by polymer shells impacts cell nucleation efficiency in CO2 blown polymer foams. Core–shell nanoparticles (NPs) with a 80 nm silica core and various polymer shells including polystyrene (PS), poly(dimethylsiloxane) (PDMS), poly(methyl methacrylate) (PMMA), and poly(acrylonitrile) (PAN) are prepared and used as heterogeneous nucleation agents to obtain CO2 blown PMMA and PS micro- and nanocellular foams. Fourier transform infrared spectroscopy, thermogravimetric analysis, and transmission electron microscopy are employed to confirm the successful synthesis of core–shell NPs. The cell size and cell density are determined by scanning electron microscopy. Silica NPs grafted with a thin PDMS shell layer exhibit the highest nucleation efficiency values, followed by PAN. The nucleation efficiency of PS- and PMMA-grafted NPs are comparable with the untreated particles and are significantly lower when compared to PDMS and PAN shells. Molecular dynamics simulations (MDS) are employed to better understand CO2 absorption and nucleation, in particular to study the impact of interfacial properties and CO2-philicity. The MDS results show that the incompatibility between particle shell layers and the polymer matrix results in immiscibility at the interface area, which leads to a local accumulation of CO2 at the interfaces. Elevated CO2 concentrations at the interfaces combined with the high interfacial tension (caused by the immiscibility) induce an energetically favorable cell nucleation process. These findings emphasize the importance of interfacial effects on cell nucleation and provide guidance for designing new, highly efficient nucleation agents in nanocellular polymer foaming.
- Published
- 2021
8. Bubble Seeding Nanocavities
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Joost Duvigneau, Shanqiu Liu, G. Julius Vancso, Sida Yin, and Materials Science and Technology of Polymers
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Thermogravimetric analysis ,Materials science ,Nanocellular materials ,Scanning electron microscope ,Nucleation ,UT-Hybrid-D ,General Physics and Astronomy ,Nanoparticle ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,CO capillary condensation ,Article ,chemistry.chemical_compound ,Core-shell nanoparticles ,Blowing agent ,General Materials Science ,CO2 capillary condensation ,Coalescence (physics) ,chemistry.chemical_classification ,Polydimethylsiloxane ,General Engineering ,Polymer ,021001 nanoscience & nanotechnology ,core−shell nanoparticles ,0104 chemical sciences ,Nanocavity ,chemistry ,Chemical engineering ,Polymer foam ,0210 nano-technology - Abstract
We describe a successful strategy to substantially enhance cell nucleation efficiency in polymer foams by using designer nanoparticles as nucleating agents. Bare and poly(dimethylsilane) (PDMS)-grafted raspberry-like silica nanoparticles with diameters ranging from ∼80 nm to ∼200 nm were synthesized and utilized as highly efficient cell nucleators in CO2-blown nanocellular polymethyl methacrylate (PMMA) foams. The successful synthesis of core–shell nanoparticles was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, Brunauer–Emmett–Teller measurements, and transmission electron microscopy. The cell size and cell density of the obtained PMMA micro- and nanocellular foams were determined by scanning electron microscopy. The results show that increased surface roughness enhances the nucleation efficiency of the designer silica particles. This effect is ascribed to a decreased nucleation free energy for foam cell nucleation in the nanocavities at the melt–nucleator interface. For PDMS grafted raspberry-like silica nanoparticles with diameters of 155 and 200 nm, multiple cell nucleation events were observed. These hybrid particles had nucleation efficiencies of 3.7 and 6.2, respectively. The surprising increase in nucleation efficiency to above unity is ascribed to the significant increase in CO2 absorption and capillary condensation in the corresponding PMMA during saturation. This increase results in the presence of large amounts of the physical blowing agent close to energetically favorable nucleation points. Additionally, it is shown that as a consequence of cell coalescence, the increased number of foam cells is rapidly reduced during the first seconds of foaming. Hence, the design of highly efficient nucleating particles, as well as careful selection of foam matrix materials, seems to be of pivotal importance for obtaining polymer cellular materials with cell dimensions at the nanoscale. These findings contribute to the fabrication of polymer foams with high thermal insulation capacity and have relevance in general to the area of cellular materials.
- Published
- 2020
9. Highly Stable and Nonflammable Hydrated Salt-Paraffin Shape-Memory Gels for Sustainable Building Technology
- Author
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Yunchong Zhang, Xueling Feng, Yan Wang, G. Julius Vancso, Feifei Wang, Zhiping Mao, Joost Duvigneau, Xiaofeng Sui, Bijia Wang, Sustainable Polymer Chemistry, MESA+ Institute, and Materials Science and Technology of Polymers
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chemistry.chemical_classification ,Materials science ,Renewable Energy, Sustainability and the Environment ,General Chemical Engineering ,Disodium hydrogen phosphate dodecahydrate ,UT-Hybrid-D ,Salt (chemistry) ,Shape-stable materials ,Nonflammable ,General Chemistry ,Shape-memory alloy ,Emulsion gel ,Eicosane ,Building thermal management ,Phase change ,chemistry ,Chemical engineering ,Environmental Chemistry ,Architectural technology ,Cohesive energy - Abstract
Hydrated salts (salt hydrates) are highly promising low-temperature phase change materials (PCMs) due to their high cohesive energy density and low cost. However, they exhibit phase separation, liquid leakage, and inherent supercooling, which hinder their applications in sustainable building technology. Here, we describe the design of a highly stable emulsion gel system (EmulGels) that exhibits nonflammable and shape-memory characteristics. Oleophilic paraffin and hydrophilic hydrated salts, both of which are excellent PCMs typically existing in separate phases, are combined harmoniously in a gel by a templating water-in-oil Pickering emulsion. Latent heat values of the prepared EmulGels were up to 213.2 J/g (eicosane/disodium hydrogen phosphate dodecahydrate = 1:3). No leakage of eicosane was noticed after heating the EmulGels at 60 °C for 30 min, and the latent heat value remained almost unchanged following 500 thermal cycles. The EmulGel was specifically designed to enable dual-phase crosslinking, which effectively enhanced its shape stability, slowed down loss of water of crystallization in hydrated salts, and decreased the degree of supercooling. Nonflammable characteristic typically found in hydrated salts was also exhibited by the EmulGel, in combination with good mechanical properties. The materials characteristics make EmulGels ideal candidates to serve as building construction interlayers for effective thermal building management.
- Published
- 2021
10. Adhesion Engineering in Polymer-Metal Comolded Joints with Biomimetic Polydopamine
- Author
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Georgios Kafkopoulos, G. Julius Vancso, Clemens J. Padberg, Joost Duvigneau, Sustainable Polymer Chemistry, and MESA+ Institute
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Materials science ,Indoles ,Polymers ,UT-Hybrid-D ,chemistry.chemical_element ,02 engineering and technology ,engineering.material ,010402 general chemistry ,01 natural sciences ,Metal ,chemistry.chemical_compound ,Engineering ,Coating ,Biomimetic Materials ,Copolymer ,Polymethyl Methacrylate ,General Materials Science ,polymer-metal adhesion ,titanium ,Methyl methacrylate ,polydopamine ,Adhesiveness ,coating ,Adhesion ,021001 nanoscience & nanotechnology ,Amides ,comolding ,PMMA ,0104 chemical sciences ,polymer−metal joint ,Chemical engineering ,chemistry ,polymer-metal joint ,polymer−metal adhesion ,Metals ,visual_art ,engineering ,visual_art.visual_art_medium ,Surface modification ,0210 nano-technology ,Layer (electronics) ,Titanium ,Research Article - Abstract
Joints that connect thermoplastic polymer matrices (TPMs) and metals, which are obtained by comolding, are of growing importance in numerous applications. The overall performance of these constructs is strongly impacted by the TPM-metal interfacial strength, which can be tuned by tailoring the surface chemistry of the metal prior to the comolding process. In the present work, a model TPM-metal system consisting of poly(methyl methacrylate) (PMMA) and titanium is used to prepare comolded joints. The interfacial adhesion is quantified by wire pullout experiments. Pullout tests prior to and following surface modification are performed and analyzed. Unmodified wires show poor interfacial strength, with a work of adhesion (Ga) value of 3.8 J m-2. To enhance interfacial adhesion, a biomimetic polydopamine (PDA) layer is first deposited on titanium followed by a second layer of a poly(methyl methacrylate-co-methacrylic acid) (P(MMA-co-MAA)) copolymer prior to comolding. During processing, the MAA moieties of the copolymer thermally react with PDA, forming amide bonds, while MMA promotes the formation of secondary bonds and molecular interdigitation with the PMMA matrix. Control testing reveals that neither PDA nor the copolymer provides a substantial increase in adhesion. However, when used in combination, a significant increase in adhesion is detected. This observation indicates a pronounced synergistic effect between the two layers that strengthens the PMMA-titanium bonding. Enhanced adhesion is optimized by tuning the MMA-to-MAA ratio of the copolymer, which shows a maximum at a 24% MAA content and a greatly increased Ga value of 155 J m-2; this value corresponds to a 40-fold increase. Further growth in the Ga values at higher MAA contents is hindered by the thermal cross-linking of MAA; MAA contents above 24% restrict the formation of secondary bonds and molecular interdigitation with the PMMA chains. Our results provide new design principles to produce thermoplastic-metal comolded joints with strong interfaces.
- Published
- 2021
11. Surface-initiated ATRP from polydopamine-modified TiO2 nanoparticles
- Author
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Joost Duvigneau, Elio Scavo, Maciej Kopeć, Järvi Spanjers, Dennis Ernens, G. Julius Vancso, and Materials Science and Technology of Polymers
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Polydopamine ,Materials science ,Polymers and Plastics ,Reducing agent ,Butyl acrylate ,UT-Hybrid-D ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Nanocomposites ,Catalysis ,chemistry.chemical_compound ,Bromide ,Lubrication ,Polymer chemistry ,Materials Chemistry ,Methyl methacrylate ,Grafting from ,chemistry.chemical_classification ,Atom-transfer radical-polymerization ,Organic Chemistry ,technology, industry, and agriculture ,Polymer ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Polymerization ,Titanium dioxide ,0210 nano-technology ,SI-ATRP - Abstract
A robust approach for modification of TiO2 nanoparticles with polymer brushes by atom transfer radical polymerization (ATRP) is presented. TiO2 surface was first coated with polydopamine (PDA) followed by immobilization of an ATRP initiator, α-bromoisobutyryl bromide (BiBB). Poly(methyl methacrylate) (PMMA) and poly(butyl acrylate) (PBA) were then grafted from the PDA-modified TiO2 of different size (25 and 300 nm) in DMF at room temperature via supplemental activator reducing agent (SARA) ATRP using only 100 ppm of the copper catalyst. Hybrid core-shell particles with high organic contents (40–88 wt%) and grafting densities (0.16–0.25 nm−2) were obtained. Reaction conducted in the presence of sacrificial initiator confirmed excellent control over the polymerization and produced PMMA and PBA with narrow molecular weight distributions (Mw/Mn < 1.25). Obtained particles were tested as lubricating additives in pipe dope compositions. Addition of polymer-grafted TiO2 to the base grease resulted in a reduced coefficient of friction (COF) and wear over uncoated TiO2 as revealed by reciprocating pin-on-disc tests. The model pipe dopes with PMMA-grafted particles were found to perform on par with commercial American Petroleum Institute (API) dope.
- Published
- 2018
12. Size-Dependent Submerging of Nanoparticles in Polymer Melts: Effect of Line Tension
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Anupam Pandey, Julius Vancso, Joost Duvigneau, Shanqiu Liu, Jacco H. Snoeijer, Materials Science and Technology of Polymers, and Physics of Fluids
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chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Capillary action ,Organic Chemistry ,Size dependent ,UT-Hybrid-D ,Nanoparticle ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Article ,Viscoelasticity ,0104 chemical sciences ,Inorganic Chemistry ,Silica nanoparticles ,chemistry ,Materials Chemistry ,Composite material ,Elasticity (economics) ,0210 nano-technology ,Glass transition - Abstract
Adhesion of nanoparticles to polymer films plays a key role in various polymer technologies. Here we report experiments that reveal how silica nanoparticles adhere to a viscoelastic PMMA film above the glass transition temperature. The polymer was swollen with CO2, closely matching the conditions of nanoparticle-nucleated polymer foaming. It is found that the degree by which the particles sink into the viscoelastic substrate is strongly size dependent and can even lead to complete engulfment for particles of diameter below 12 nm. These findings are explained quantitatively by a thermodynamic analysis, combining elasticity, capillary adhesion, and line tension. We argue that line tension, here proposed for the first time in elastic media, is responsible for the nanoparticle engulfment.
- Published
- 2018
13. Silica-Assisted Nucleation of Polymer Foam Cells with Nanoscopic Dimensions: Impact of Particle Size, Line Tension, and Surface Functionality
- Author
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Joost Duvigneau, G. Julius Vancso, Shanqiu Liu, Rik Eijkelenkamp, and Materials Science and Technology of Polymers
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Materials science ,Scanning electron microscope ,Nucleation ,Nanoparticle ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Line tension ,General Materials Science ,Fourier transform infrared spectroscopy ,Composite material ,Nanocomposite ,Interface ,021001 nanoscience & nanotechnology ,Surface energy ,0104 chemical sciences ,Nanocellular foam ,Surface functionalization ,2023 OA procedure ,highly curved core−shell nanoparticle ,Heterogeneous foam cell nucleation ,Surface modification ,Highly curved core-shell nanoparticle ,Particle size ,0210 nano-technology ,Research Article - Abstract
Core-shell nanoparticles consisting of silica as core and surface-grafted poly(dimethylsiloxane) (PDMS) as shell with different diameters were prepared and used as heterogeneous nucleation agents to obtain CO2-blown poly(methyl methacrylate) (PMMA) nanocomposite foams. PDMS was selected as the shell material as it possesses a low surface energy and high CO2-philicity. The successful synthesis of core-shell nanoparticles was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, and transmission electron microscopy. The cell size and cell density of the PMMA micro- and nanocellular materials were determined by scanning electron microscopy. The cell nucleation efficiency using core-shell nanoparticles was significantly enhanced when compared to that of unmodified silica. The highest nucleation efficiency observed had a value of ∼0.5 for nanoparticles with a core diameter of 80 nm. The particle size dependence of cell nucleation efficiency is discussed taking into account line tension effects. Complete engulfment by the polymer matrix of particles with a core diameter below 40 nm at the cell wall interface was observed corresponding to line tension values of approximately 0.42 nN. This line tension significantly increases the energy barrier of heterogeneous nucleation and thus reduces the nucleation efficiency. The increase of the CO2 saturation pressure to 300 bar prior to batch foaming resulted in an increased line tension length. We observed a decrease of the heterogeneous nucleation efficiency for foaming after saturation with CO2 at 300 bar, which we attribute to homogenous nucleation becoming more favorable at the expense of heterogeneous nucleation in this case. Overall, it is shown that the contribution of line tension to the free energy barrier of heterogeneous foam cell nucleation must be considered to understand foaming of viscoelastic materials. This finding emphasizes the need for new strategies including the use of designer nucleating particles to enhance the foam cell nucleation efficiency.
- Published
- 2017
14. Printing 'smart' Inks of Redox-Responsive Organometallic Polymers on Microelectrode Arrays for Molecular Sensing
- Author
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G. Julius Vancso, Joost Duvigneau, Remko Akkerman, Mark A. Hempenius, Jinmeng Hao, T.C. Bor, Marco Cirelli, Niels Benson, Materials Science and Technology of Polymers, and Production Technology
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Materials science ,Poly(ferrocenylsilane) (PFS) ,Drop-on-demand (DoD) ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Contact angle ,Gel permeation chromatography ,Electrochemical sensors ,General Materials Science ,Elektrotechnik ,chemistry.chemical_classification ,Microelectrode array (MEA) chip ,Polymer ,021001 nanoscience & nanotechnology ,Ascorbic acid ,0104 chemical sciences ,Electrochemical gas sensor ,Microelectrode ,Inkjet printing ,chemistry ,Electrode ,Cyclic voltammetry ,0210 nano-technology ,Research Article - Abstract
Printing arrays of responsive spots for multiplexed sensing with electrochemical readout requires new molecules and precise, high-throughput deposition of active compounds on microelectrodes with spatial control. We have designed and developed new redox-responsive polymers, featuring a poly(ferrocenylsilane) (PFS) backbone and side groups with disulfide units, which allow an efficient and stable bonding to Au substrates, using sulfur-gold coupling chemistry in a "grafting-to" approach. The polymer molecules can be employed for area selective molecular sensing following their deposition by high-precision inkjet printing. The new PFS derivatives, which serve as "molecular inks", were characterized by 1H NMR, 13C NMR, and FTIR spectroscopies and by gel permeation chromatography. The viscosity and surface tension of the inks were assessed by rheology and pendant drop contact angle measurements, respectively. Commercial microelectrode arrays were modified with the new PFS ink by using inkjet printing in the "drop-on-demand" mode. FTIR spectroscopy, AFM, and EDX-SEM confirmed a successful, spatially localized PFS modification of the individual electrodes within the sensing cells of the microelectrode arrays. The potential application of these devices to act as an electrochemical sensor array was demonstrated with a model analyte, ascorbic acid, by using cyclic voltammetry and amperometric measurements.
- Published
- 2019
15. Nanocellular polymer foams nucleated by core-shell nanoparticles
- Author
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G. Julius Vancso, Joost Duvigneau, Shanqiu Liu, Bram Zoetebier, Lars Hulsman, Yuanyuan Zhang, Faculty of Science and Technology, Materials Science and Technology of Polymers, and Developmental BioEngineering
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chemistry.chemical_classification ,Thermogravimetric analysis ,Materials science ,Polymers and Plastics ,Scanning electron microscope ,Organic Chemistry ,Nucleation ,Nanoparticle ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,2023 OA procedure ,Materials Chemistry ,Surface modification ,Polystyrene ,Composite material ,Fourier transform infrared spectroscopy ,0210 nano-technology - Abstract
The synthesis of low surface energy polymer grafted silica nanoparticles is reported for the utilization as highly efficient cell nucleation agents to obtain nanocellular, CO2 blown polystyrene (PS) and poly(methyl methacrylate) (PMMA) films in a batch process. For nanoparticle surface functionalization hydroxyl-terminated perfluoropolyether and poly(dimethylsiloxane) (PDMS) were used. Their successful grafting to silica nanoparticles was confirmed by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). Following melt blending of the modified silica nanoparticles with PS or PMMA their dispersions were evaluated by scanning electron microscopy (SEM) analyses. We demonstrate that proper selection of the polymer grafts results in nucleation efficiencies of up to approximately 0.5 (i.e. 1 foam cell per 2 particles on average), which is the highest value reported so far for nanofillers as nucleation agents. This number was confirmed by the presence of only 2 to 4 nanoparticles per cell in nanocellular PS and PMMA foams containing SiO2 nanoparticles with a PDMS shell as was observed in cross sectional SEM images. The lowest density foam we obtained (∼0.32 g cm−3) had a nanocellular morphology with a cell size and cell density of ∼440 nm and 1.85 × 1013 cells cm−3, respectively. It is shown that the use of a low surface energy thin shell around silica nanoparticles is beneficial for cell nucleation compared to untreated particles.
- Published
- 2016
16. Optical imaging beyond the diffraction limit by SNEM: Effects of AFM tip modifications with thiol monolayers on imaging quality
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Aysegul Cumurcu, I.D. Lindsay, Peter Manfred Schön, Jordi Díaz, Sissi de Beer, G. Julius Vancso, Joost Duvigneau, Faculty of Science and Technology, and Materials Science and Technology of Polymers
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Diffraction ,Materials science ,Ethanethiol ,Analytical chemistry ,Adhesion ,engineering.material ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,chemistry.chemical_compound ,Coating ,Optical microscope ,chemistry ,law ,Microscopy ,Monolayer ,2023 OA procedure ,engineering ,Instrumentation ,Nanoscopic scale - Abstract
Tip-enhanced nanoscale optical imaging techniques such as apertureless scanning near-field optical microscopy (a-SNOM) and scanning near-field ellipsometric microscopy (SNEM) applications can suffer from a steady degradation in performance due to adhesion of atmospheric contaminants to the metal coated tip. Here, we demonstrate that a self-assembled monolayer (SAM) of ethanethiol (EtSH) is an effective means of protecting gold-coated atomic force microscopy (AFM) probe tips from accumulation of surface contaminants during prolonged exposure to ambient air. The period over which they yield consistent and reproducible results for scanning near-field ellipsometric microscopy (SNEM) imaging is thus extended. SNEM optical images of a microphase separated polystyrene-block-poly (methylmethacrylate) (PS-b-PMMA) diblock copolymer film, which were captured with bare and SAM-protected gold-coated AFM probes, both immediately after coating and following five days of storage in ambient air, were compared. During this period the intensity of the optical signals from the untreated gold tip fell by 66%, while those from the SAM protected tip fell by 14%. Additionally, gold coated AFM probe tips were modified with various lengths of alkanethiols to measure the change in intensity variation in the optical images with SAM layer thickness. The experimental results were compared to point dipole model calculations. While a SAM of 1-dodecanethiol (DoSH) was found to strongly suppress field enhancement we find that it can be locally removed from the tip apex by deforming the molecules under load, restoring SNEM image contrast.
- Published
- 2015
17. Raft crystals of poly(isoprene)-block-poly(ferrocenyldimethylsilane) and their surface wetting behavior during melting as observed by AFM and NanoTA
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G. Julius Vancso, In Yee Phang, Hairong Wu, Mark A. Hempenius, Hong Jing Chung, Ian Manners, Siti Fairus Mohd Yusoff, Lionel Dos Ramos, E. Kutnyanszky, Joost Duvigneau, Torben Gädt, Faculty of Science and Technology, and Materials Science and Technology of Polymers
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Nanostructure ,Materials science ,Polymers and Plastics ,Silicon ,Organic Chemistry ,chemistry.chemical_element ,Substrate (electronics) ,Surface energy ,Crystallography ,chemistry ,2023 OA procedure ,Materials Chemistry ,Lamellar structure ,Wetting ,Pyrolytic carbon ,Wetting layer - Abstract
We report on the morphology evolution during heating and melting of lamellar poly(isoprene)-block-poly(ferrocenyldimethylsilane) (PI76-b-PFDMS76) raft crystals deposited at the native oxide surface of silicon (SiO2) or at a highly ordered pyrolytic graphite (HOPG) surface, studied by in situ temperature controlled atomic force microscopy. Crystals deposited on hydrophilic SiO2 surfaces revealed an irreversible decrease in length at temperatures of up to tens of degrees above their expected melting temperature, while maintaining their platelet-like structure. Crystals deposited on hydrophobic HOPG surfaces initially decreased in length below their expected melting temperature, while at 120 °C and above a typical molten morphology was observed. In addition, the irreversible formation of a PI76-b-PFDMS76 wetting layer around the crystals was observed upon increasing the temperature. These observations in the morphological behavior upon heating emphasize the role of interfacial energy between a surface deposited block copolymer based macromolecular nanostructure and its supporting substrate.
- Published
- 2014
18. Multimodal imaging of heterogeneous polymers at the nanoscale by AFM and scanning near-field ellipsometric microscopy
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Joost Duvigneau, Aysegul Cumurcu, I.D. Lindsay, Gyula J. Vancso, Peter Manfred Schön, Faculty of Science and Technology, and Materials Science and Technology of Polymers
- Subjects
Diffraction ,Microscope ,Materials science ,Polymers and Plastics ,Silicon ,business.industry ,Organic Chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Near and far field ,Dielectric ,law.invention ,Optics ,chemistry ,law ,Ellipsometry ,2023 OA procedure ,Microscopy ,Materials Chemistry ,Thin film ,business - Abstract
Scanning near field ellipsometric microscopy (SNEM) was used to simultaneously obtain optical images and tapping mode topography images of the microphase separated morphology of PS-b-P2VP block copolymer thin films. Optical images revealed a spatial resolution well below the diffraction limit. The SNEM setup used consisted of an AFM and an ellipsometer that were commercially available and that did not require major changes in their design to build the hybrid microscope. The observed increase in optical contrast for gold coated tips compared to silicon AFM probe tips was in qualitative agreement with the calculated increase in scattering amplitude according to the point dipole model for a gold AFM probe tip compared to a bare silicon AFM probe tip of the same size. The dielectric constant difference between the two blocks of the diblock copolymer was increased by selectively staining the P2VP block with iodine vapor. This resulted in an increase in the optical contrast between the PS and P2VP domains. Furthermore, the decrease in optical contrast as a function of increasing tip-sample separation was studied. It was observed that at 50 nm tip sample separation the optical contrast was significantly reduced. The non-linear decay of the near-field amplitude signal as a function of the tip-sample separation calculated with the point dipole model supported this experimental result. The use of tapping mode in SNEM opens novel opportunities to study soft matter down to the macromolecular level.
- Published
- 2013
19. Reactive Imprint Lithography: Combined Topographical Patterning and Chemical Surface Functionalization of Polystyrene-block-poly(tert-butyl acrylate) Films
- Author
-
Stijn Cornelissen, Holger Schönherr, G. Julius Vancso, Núria Bardají Valls, Joost Duvigneau, Materials Science and Technology of Polymers, and Faculty of Science and Technology
- Subjects
chemistry.chemical_classification ,Acrylate ,Materials science ,Polymer films ,Polymer ,Thermal activation ,Condensed Matter Physics ,METIS-269873 ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Patterning ,chemistry.chemical_compound ,Adsorption ,Chemical engineering ,X-ray photoelectron spectroscopy ,chemistry ,Surface functionalization ,Polymer chemistry ,2023 OA procedure ,Electrochemistry ,Surface modification ,Polystyrene ,Reactive imprint lithography ,Glass transition ,Layer (electronics) - Abstract
Here, reactive imprint lithography (RIL) is introduced as a new, one-step lithographic tool for the fabrication of large-area topographically patterned, chemically activated polymer platforms. Films of polystyrene-block-poly(tert-butyl acrylate) (PS-b-PtBA) are imprinted with PDMS master stamps at temperatures above the corresponding glass transition and chemical deprotection temperatures to yield structured films with exposed carboxylic acid and anhydride groups. Faithful pattern transfer is confirmed by AFM analyses. Transmission-mode FTIR spectra shows a conversion of over 95% of the tert-butyl ester groups after RIL at 230 °C for 5 minutes and a significantly reduced conversion to anhydride compared to thermolysis of neat films with free surfaces in air or nitrogen. An enrichment of the surface layer in PS is detected by angle-resolved X-ray photoelectron spectroscopy (XPS). In order to demonstrate application potentials of the activated platforms, a 7 nm ± 1 nm thick NH2-terminated PEG layer (grafting density of 0.9 chains nm−2) is covalently grafted to RIL-activated substrates. This layer reduces the non-specific adsorption (NSA) of bovine serum albumin by 95% to a residual mass coverage of 9.1 ± 2.9 ng cm−2. As shown by these examples, RIL comprises an attractive complementary approach to produce bio-reactive polymer surfaces with topographic patterns in a one-step process.
- Published
- 2010
20. Atomic Force Microscopy Based Thermal Lithography of Poly(tert-butyl acrylate) Block Copolymer Films for Bioconjugation
- Author
-
G. Julius Vancso, Holger Schönherr, Joost Duvigneau, Faculty of Science and Technology, and Materials Science and Technology of Polymers
- Subjects
Materials science ,Biocompatible Materials ,Scanning thermal microscopy ,Microscopy, Atomic Force ,Micrometre ,chemistry.chemical_compound ,Spectroscopy, Fourier Transform Infrared ,Polymer chemistry ,Electrochemistry ,Copolymer ,General Materials Science ,Fourier transform infrared spectroscopy ,Spectroscopy ,chemistry.chemical_classification ,Acrylate ,Molecular Structure ,Temperature ,Water ,Chemical modification ,Surfaces and Interfaces ,Polymer ,Condensed Matter Physics ,Kinetics ,Acrylates ,chemistry ,2023 OA procedure ,Ethylene glycol - Abstract
In this paper, we report on the local thermal activation of thin polymer films for area-selective surface chemical modification on micrometer and nanometer length scales. The thermally induced activation of tert-butyl ester moieties in polystyrene- block-poly(tert-butyl acrylate) (PS- b-PtBA) block copolymer films leads to the formation of pending carboxylic acid groups, which are among the versatile functionalities for subsequent bioconjugation. From Fourier transform infrared (FTIR) spectroscopic analyses, the apparent activation energy (Ea) for the tert-butyl ester deprotection in thin films was calculated to be 93 +/- 12 kJ/mol, which is in good agreement with values reported for the bulk. The availability of the deprotected carboxylic acid groups in subsequent wet chemical grafting reactions on neat thermolyzed films was confirmed by covalently immobilizing fluoresceinamine and amino end-functionalized poly(ethylene glycol) (PEG-NH2) using established 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) chemistry. Local thermal deprotection on micrometer and sub-micrometer length scales was achieved by scanning thermal microscopy using an atomic force microscope with heatable probe tips. Passivating PEG and fluoresceinamine layers were selectively covalently coupled to locally deprotected areas as small as 370 nm x 580 nm.
- Published
- 2008
21. Nanocellular polymer foams as promising high performance thermal insulation materials
- Author
-
Gyula J. Vancso, Joost Duvigneau, Shanqiu Liu, Faculty of Science and Technology, and Materials Science and Technology of Polymers
- Subjects
chemistry.chemical_classification ,Nanocomposite ,Materials science ,Polymers and Plastics ,Polymer nanocomposite ,business.industry ,Organic Chemistry ,Nucleation ,General Physics and Astronomy ,Nanotechnology ,Polymer ,chemistry ,Thermal insulation ,2023 OA procedure ,Materials Chemistry ,Low density ,business ,Nanoscopic scale - Abstract
Low density, nanocellular polymer nanocomposite foams are considered as a promising new class of materials with many promising applications, for example to passively enhance the energy efficiency of buildings. This paper discusses recent developments in this field of polymer materials science. Particular attention will be devoted to CO2 based foaming strategies. Emphasis is on new insights concerning heterogeneous nucleation at the macromolecular length scale and the thermal insulation performance of nanocellular polymer foams. Furthermore, we discuss the limitations and challenges that remain to be solved before these highly promising nanocomposites become available on a commercially viable scale. The shortcomings in the understanding the fundamental principles involved in cell nucleation in polymer nanocomposites at the nanoscale are elucidated.
- Published
- 2015
22. Nanoscale scanning near-field ellipsometric microscopy (SNEM) imaging of heterogeneous polymers
- Author
-
Aysegul Cumurcu, G. Julius Vancso, Peter Manfred Schön, I.D. Lindsay, and Joost Duvigneau
- Subjects
Scanning probe microscopy (SPM) ,Materials science ,Microscope ,Optical properties ,business.industry ,Scanning confocal electron microscopy ,Scanning capacitance microscopy ,law.invention ,Scanning probe microscopy ,Nanoscale ,Ellipsometry ,law ,Microscopy ,Scanning ion-conductance microscopy ,Optoelectronics ,business ,NLA ,Vibrational analysis with scanning probe microscopy - Abstract
In this study a scanning near-field ellipsometric microscope (SNEM), a hybrid device of an atomic force microscope (AFM) and an ellipsometer, is used to obtain optical images of heterogeneous polymer thin films with a resolution below the diffraction limit of light. SNEM optical images of a microphase separated PS-b-P2VP block copolymer film collected with gold coated and bare silicon AFM probe tips were compared to obtain a deeper insight into the nature of the SNEM contrast mechanism. Furthermore, intensity vs. distance curves were recorded on a PS-b-PMMA block copolymer film simultaneously during the acquisition of force-displacement curves to study the far-field contribution of the optical signal to the optical image.
- Published
- 2014
23. Scanning thermal lithography of tailored tert-butyl ester protected carboxylic acid functionalized (meth)acrylate polymer platforms
- Author
-
G. Julius Vancso, Holger Schönherr, Joost Duvigneau, and Materials Science and Technology of Polymers
- Subjects
Acrylate polymer ,Isobutylene ,Thermogravimetric analysis ,Acrylate ,Materials science ,Depolymerization ,Thermal decomposition ,Radical polymerization ,Methacrylate ,chemistry.chemical_compound ,chemistry ,Polymer chemistry ,2023 OA procedure ,General Materials Science - Abstract
In this paper, we report on the development of tailored polymer films for high-resolution atomic force microscopy based scanning thermal lithography (SThL). In particular, full control of surface chemical and topographical structuring was sought. Thin cross-linked films comprising poly(tert-butyl methacrylate) (MA(20)) or poly(tert-butyl acrylate) (A(20)) were prepared via UV initiated free radical polymerization. Thermogravimetric analysis (TGA) and FTIR spectroscopy showed that the heat-induced thermal decomposition of MA(20) by oxidative depolymerization is initially the primary reaction followed by tert-butyl ester thermolysis. By contrast, no significant depolymerization was observed for A(20). For A(20) and MA(20) (at higher temperatures and/or longer reaction times) the thermolysis of the tert-butyl ester liberates isobutylene and yields carboxylic acid groups, which react further intramolecularly to cyclic anhydrides. The values of the apparent activation energies (E(a)) for the thermolysis were calculated to be 125 ± 13 kJ mol(-1) and 116 ± 7 kJ mol(-1) for MA(20) and A(20), respectively. Both MA(20) and A(20) films showed improved thermomechanical stability during SThL compared to non cross-linked films. Carboxylic acid functionalized lines written by SThL in A(20) films had a typically ~10 times smaller width compared to those written in MA(20) films regardless of the tip radius of the heated probe and did not show any evidence for thermochemically or thermomechanically induced modification of film topography. These observations and the E(a) of 45 ± 3 kJ mol(-1) for groove formation in MA(20) estimated from the observed volume loss are attributed to oxidative thermal depolymerization during SThL of MA(20) films, which is considered to be the dominant reaction mechanism for MA(20). The smallest line width values obtained for MA(20) and A(20) films with SThL were 83 ± 7 nm and 21 ± 2 nm, whereas the depth of the lines was below 1 nm, respectively.
- Published
- 2011
24. Scanning thermal lithography as a tool for highly localized nanoscale chemical surface functionalization
- Author
-
G. Julius Vancso, Joost Duvigneau, Holger Schönherr, and Materials Science and Technology of Polymers
- Subjects
chemistry.chemical_classification ,Acrylate ,Materials science ,Nanotechnology ,Polymer ,chemistry.chemical_compound ,chemistry ,Scanning ion-conductance microscopy ,Thermochemistry ,Molecule ,Surface modification ,Lithography ,Nanoscopic scale ,NLA - Abstract
We report on Scanning Thermal Lithography (SThL), a recently introduced lithographic tool, for local thermochemistry on tert-butyl acrylate based polymer films featuring chemical cross links. The tailored polymer films afford platforms for controlled high molecular density coupling and surface immobilization of biologically relevant molecules, such as proteins. The thermally labile tert-butyl ester groups in tert-butyl acrylate based polymer films can be cleaved in air at temperatures above 150 °C to yield carboxylic acid functional groups for further (bio)- conjugation. The films were optimized to avoid plastic deformation at the elevated temperatures used during SThL. Exploiting these properties patterns with length scales as small as 35 ± 6 nm have been successfully thermally activated with SThL. Hence SThL comprises an attractive approach for the development of e.g. (bio)sensors and platforms for cell surface interaction studies with nanoscale patterns.
- Published
- 2011
25. Atomic Force Microscopy Based Thermal Lithography of Poly(tert-butyl acrylate) Block Copolymer Films for Bioconjugation.
- Author
-
Joost Duvigneau, Holger Schönherr, and G. Julius Vancso
- Subjects
- *
POLYMERS , *MICROSCOPY , *THIN films , *ETHYLENE glycol - Abstract
In this paper, we report on the local thermal activation of thin polymer films for area-selective surface chemical modification on micrometer and nanometer length scales. The thermally induced activation of tert-butyl ester moieties in polystyrene- block-poly( tert-butyl acrylate) (PS- b-P tBA) block copolymer films leads to the formation of pending carboxylic acid groups, which are among the versatile functionalities for subsequent bioconjugation. From Fourier transform infrared (FTIR) spectroscopic analyses, the apparent activation energy ( Ea) for the tert-butyl ester deprotection in thin films was calculated to be 93 ± 12 kJ/mol, which is in good agreement with values reported for the bulk. The availability of the deprotected carboxylic acid groups in subsequent wet chemical grafting reactions on neat thermolyzed films was confirmed by covalently immobilizing fluoresceinamine and amino end-functionalized poly(ethylene glycol) (PEG-NH 2) using established 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC)/ N-hydroxysuccinimide (NHS) chemistry. Local thermal deprotection on micrometer and sub-micrometer length scales was achieved by scanning thermal microscopy using an atomic force microscope with heatable probe tips. Passivating PEG and fluoresceinamine layers were selectively covalently coupled to locally deprotected areas as small as 370 nm × 580 nm. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
26. Development of multifunctional complex fluids for coating of semi-porous surfaces
- Author
-
Marco Cirelli, Joost Duvigneau, Gyula Julius Vancso, Remko Akkerman, and Materials Science and Technology of Polymers
- Subjects
METIS-319825 ,METIS-319824
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