Nanopatterned polymer brushes by reactive writing

Nawroth, Jonas F.; Neisser, Claudia; Erbe, Artur; Jordan, Rainer

doi:10.1039/c5nr08282j

Cited by 8 publications

(8 citation statements)

References 35 publications

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“…The faster grafting kinetics of SI-ATRP under confinement might have a significant impact on systems involving polymer growth within nano/microstructured environments and can be exploited to structure polymer interfaces with high precision and reproducibility. Although efforts have been increasingly spent by us and others in proposing accessible methods for the fabrication of nanostructured polymer brushes − and brush gradients − by SI-CRP, these often rely on sophisticated and sometimes tedious multistep, surface-modification protocols, which frequently suffer from a lack of reproducibility. An experimentally simple demonstration of the intrinsic applicability of confined SI-ATRP to synthesize nanostructured polymeric platforms is provided by the fabrication of polymer-brush gradients, utilizing an initiating substrate presenting a confining surface, positioned at a variable distance (“tilted” confining plane, as schematically depicted in Figure a).…”

Section: Resultsmentioning

confidence: 99%

Modulation of Surface-Initiated ATRP by Confinement: Mechanism and Applications

et al. 2017

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The mechanism of surface-initiated atom transfer polymerization (SI-ATRP) of methacrylates in confined volumes is systematically investigated by finely tuning the distance between a grafting surface and an inert plane by means of nanosized patterns and micrometer thick foils. The polymers were synthesized from monolayers of photocleavable initiators, which allow the analysis of detached brushes by size-exclusion chromatography (SEC). Compared to brushes synthesized under “open” polymerization mixtures, nearly a 4-fold increase in brush molar mass was recorded when SI-ATRP was performed within highly confined reaction volumes. Correlating the SI-ATRP of methyl methacrylate (MMA), with and without “sacrificial” initiator, to that of lauryl methacrylate (LMA) and analyzing the brush growth rates within differently confined volumes, we demonstrate faster grafting kinetics with increasing confinement due to the progressive hindering of CuII-based deactivators from the brush propagating front. This effect is especially noticeable when viscous polymerization mixtures are generated and enables the synthesis of several hundred nanometer thick brushes within relatively short polymerization times. The faster rates of confined SI-ATRP can be additionally used to fabricate, in one pot, precisely structured brush gradients, when volume confinement is continuously varied across a single substrate by spatially tuning the vertical distance between the grafting and the confining surfaces.

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Section: Resultsmentioning

confidence: 99%

Modulation of Surface-Initiated ATRP by Confinement: Mechanism and Applications

et al. 2017

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“…Later, Wang et al demonstrated that also acrylic monomers were amenable to self-initiated polymerization and grafting, proposing in a similar manner that the self-initiation mechanism occurs via excitation of the monomer to a triplet state in equilibrium with a biradical form of the vinyl group, with sufficient energy to abstract hydrogen from an organic substrate and initiate the grafting . Despite the simple and widely applicable implementation of the SI-PGP method, it is still not widespread, but the literature demonstrates that it is used for solving polymer coating problems in many different applications. − …”

Section: Introductionmentioning

confidence: 99%

Structure and pH-Induced Swelling of Polymer Films Prepared from Sequentially Grafted Polyelectrolytes

et al. 2022

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We have prepared a series of ampholytic polymer films, using a self-initiated photografting and photopolymerization (SI-PGP) method to sequentially polymerize first anionic (deuterated methacrylic acid (dMAA)) and thereafter cationic (2-aminoethyl methacrylate (AEMA)) monomers to investigate the SI-PGP grafting process. Dry films were investigated by ellipsometry, X-ray, and neutron reflectometry, and their swelling was followed over a pH range from 4.5 to 10.5 with spectroscopic ellipsometry. The deuterated monomer allows us to separate the distributions of the two components by neutron reflectometry. Growth of both polymers proceeds via grafting of solution-polymerized fragments to the surface, and also the second layer is primarily grafted to the substrate and not as a continuation of the existing chains. The polymer films are stratified, with one layer of near 1:1 composition and the other layer enriched in one component and located either above or below the former layer. The ellipsometry results show swelling transitions at low and high pH but with no systematic variation in the pH values where these transitions occur. The results suggest that grafting density in SI-PGP-prepared homopolymers could be increased via repeated polymerization steps, but that this process does not necessarily increase the average chain length.

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“…in biology and medical science for cell adhesion and separation, [1,2] and in optoelectronic devices such as microlens arrays, [3,4] photovoltaic cells or organic transistors. [3,[5][6][7][8] A widely researched field is the modification of substrates with polymer films, employing different techniques for selective deposition. Frequently used are DOI: 10.1002/macp.202200228 techniques based on the covalent attachment of polymer chains to surface functionalities, and methods of film deposition, directed by spatially different surface properties, resulting in selective deposition of so-called polymer brushes.…”

Section: Introductionmentioning

confidence: 99%

“…To prepare selective deposition of polymer brushes, the surface is typically pre-patterned in a number of possible ways, such as microcontact printing [26][27][28] , lithographic techniques [9,[29][30][31][32][33] or reactive writing techniques. [6] With these techniques, the initiator SAM can be patterned in the desired way, subsequently enabling the growth of polymer brushes in the desired structure. Due to the high precision of these techniques, brushes can be structured down into nm-sized structures.…”

Section: Introductionmentioning

confidence: 99%

Self‐Aligned Polymer Film Patterning on Microstructured Silicon Surfaces

Schutzeichel

Kiriy

et al. 2022

Macro Chemistry & Physics

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Based on a recently developed selective etching process for silicon samples with buried implants, this work presents a method for utilizing the generated material contrast between silicon and silicon oxide to selectively deposit polymers on the patterned surface. Besides depositing polystyrene selectively on the etched parts via drop-casting and dewetting, polymer chains are selectively grafted to the oxidic surface parts. To this end, the oxide surfaces are selectively modified via functional alkoxysilanes, whereas etched silicon surfaces are unreactive. Using either a two-step or a straight-forward one-step process employing commercially available chemicals, atom transfer radical polymerization (ATRP) initiator functions are attached selectively to the non-etched surface areas, and subsequently used to polymerize either methyl methacrylate (MMA) or N-isopropyl acrylamide (NIPAM) in a controlled surface-initiated activator regenerated by electron transfer (ARGET)-ATRP process. This procedure allows for the further self-aligned functionalization of the micropatterned samples, enabling the production of highly functional, patterned surfaces, potentially suitable for applications in areas such as cell adsorption, microfluidics, or functional microsystems, e.g., MEMS.

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Nanopatterned polymer brushes by reactive writing

Abstract: A self-assembled monolayer of perflourinated silanes is used to prepare nanopatterned polymer brushes and brush gradients by focused electron beam reactive writing (RW) and surface-initiated photopolymerization of vinyl monomers.

Cited by 8 publications

References 35 publications

Modulation of Surface-Initiated ATRP by Confinement: Mechanism and Applications

Modulation of Surface-Initiated ATRP by Confinement: Mechanism and Applications

Structure and pH-Induced Swelling of Polymer Films Prepared from Sequentially Grafted Polyelectrolytes

Self‐Aligned Polymer Film Patterning on Microstructured Silicon Surfaces

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