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This article categorizes and evaluates how regulatory regimes conceptualize plastics, and how such conceptualizations affect the production, consumption, and disposal of plastics. Taking a doctrinal and policy-oriented approach, it identifies four ‘frames’ – that is, four distinct and coherent sets of meanings attributed to plastics within transnational regulation – namely, plastics as waste to be managed; a material to be prevented; a good (or waste) to be traded freely; and inputs or outputs in production-consumption systems. Based on this analysis, three significant deficiencies in the transnational regulation of plastics are identified: the failure to frame plastics in terms of environmental justice and human rights issues; insufficient focus on plastics prevention (rather than management); and the role of law in reinforcing its production and consumption.

We introduce an inherently fluorescent self-reporting step-growth polymer system as well as a fluorescence-based methodology for accessing the kinetics of the underpinning photoinduced nitrile imine-mediated tetrazole-ene cycloaddition (NITEC) process, using an equimolar mixture of a bismaleimide linker and a bifunctional α,ω-tetrazole-chain transfer agent (CTA). Similarly, α,ω-tetrazole-capped polystyrene, prepared via RAFT polymerization, was employed as a photoreactive macromonomer. Upon UV irradiation, the tetrazole moiety readily reacts with activated dialkenes producing the fluorescent pyrazoline-containing polymer. Thus, the fluorescence emission of the step-growth polymers is directly correlated with the number of ligation points in the polymer, forming an ideal self-reporting sensor system. The viability of the fluorescence-based quantification is verified via NMR spectroscopy, evidencing that fluorescence-based polymerization monitoring is a viable avenue in cases where NMR spectroscopy is difficult to conduct.

Visible light-triggered reversible triazolinedione (TAD) chemistry was already reported in the 1970s but it has only recently been introduced into the field of materials science, and as such remains relatively unexplored. Here, we exploit the reversible naphthalene-TAD Diels–Alder couple to crosslink pre-synthesized polymers in a precipitation-like polymerization to form narrow disperse microparticles. The approach does not require additives such as stabilizers or initiators and proceeds to deliver particles under relatively mild conditions in less than 1 h. While the crosslinked particles maintain their shape upon continuous irradiation with green light, the particles can be readily degraded in the dark at ambient temperature through a spontaneous cycloreversion process. In addition, the formation and degradation rate can be tuned by employing shorter or longer prepolymers, with particles synthesized from larger polymers degrading slower compared to their shorter polymer counterparts. The particle formation, light-stabilization and degradation were characterized in-depth by scanning electron microscopy (SEM) and online static light scattering experiments. In particular the particles’ tuneable intrinsic degradation behaviour could hold key potential, for instance, in long term drug or fertilizer delivery systems.

Polyserotonin-based nanoparticles are a new class of bioinspired nanomaterial with recently demonstrated therapeutic potential for future clinical applications. It is therefore important to establish a robust and rapid method of synthesizing polyserotonin nanoparticles (PSeNP) in the size range ideal for in vivo utilization. Since the formation of PSeNP is base-catalyzed, here we report the influence of solution pH, in the presence of different base systems, on the kinetics of PSeNP formation and physico-chemical properties of the resulting nanoparticles. We show that the rate of formation and the size of PSeNP depend on both the nature of the base and the initial pH of the reaction. We have also improved the kinetics of particle formation by performing the synthesis at an elevated temperature (60 °C), leading to a dramatic reduction in synthesis time from days to hours. This presents a significant advance in the efficiency of PSeNP synthesis and provides a facile approach in tuning the size of nanoparticles to suit various applications. Furthermore, we show that similar to serotonin, PSeNP also exhibits free radical scavenging property. Our results demonstrate that PSeNP has the potential to become a key player in the advancement of nanotechnology-mediated antioxidative therapy.

When grafting polymers onto surfaces, the reaction conditions critically influence the resulting interface properties, including the grafting density and molar mass distribution (MMD) on the surface. Herein, we show theoretically and experimentally that the application of poor solvents is beneficial for the "grafting-to" approach. We demonstrate the effect by grafting poly(methyl methacrylate) chains on silica nanoparticles in different solvents and compare the MMD of the polymer in solution before and after grafting via size exclusion chromatography (SEC). The shorter polymer chains are preferentially grafted onto the surface, leading to a distortion effect between the MMD in solution and on surfaces. The molecular weight distortion effect is significantly higher for ethyl acetate (good solvent quality, difference in Mw surface to solution 14%) than for N,N-dimethylacetamide (poor solvent quality, 6%). The difference in MMD on the surface to the solution significantly affects both the surface properties (e.g. the grafting densities) and their determination.

Single molecule force spectroscopy (SMFS) is employed to gain insight into reversible addition–fragmentation chain transfer (RAFT) polymerization processes with living characteristics on glass surfaces. Surface-initiated (SI)-RAFT was selected to grow poly(hydroxyethyl methacrylate) (PHEMA). After aminolysis of the RAFT chain termini, thiol moieties serve as anchoring points for the gold tip of an atomic force microscope. The results allow to directly monitor the macromolecular growth of the surface-initiated polymerization. The obtained SMFS-based molecular weight distribution data of the polymers present on the surface indicate that the RAFT chain extension proceeds linearly with time up to high conversions. The current study thus adds SMFS as a valuable tool for the investigation of SI-RAFT polymerizations.

We explore a cross-linked polymer network based on a visible light photodynamic [2 + 2] cycloaddition driven by styrylpyrene chemistry. Based on a polymer backbone with pendent styrylpyrene units, the network can be formed by using λ = 450 nm irradiation. Upon irradiation with λ = 340 nm, a photostationary state is generated within the network with ∼17% of the styrylpyrene units open compared to close to 2% in the visible light cured state. The limited fraction of open [2 + 2] couples is caused by their proximity and is in sharp contrast to solution experiments on the photoreactive moiety. Thus, the polymer network retains its mechanical properties even at the photostationary point. We hypothesize that the application of an additional stimulus could serve as a second gate for inducing network disintegration by spacing the [2 + 2] units during ultraviolet irradiation.

The intramolecular chain collapse of linear precursors with systematic variation of molar mass and ligation group density (5, 15, and 30 mol %) into single-chain nanoparticles (SCNPs) was studied by two different separation approaches. The efficiency of size exclusion chromatography with quadruple detection (SEC-D4) was compared to asymmetrical field flow fractionation hyphenated to quintuple detection (AF4-D5) in organic solvent. The application of the unique combination of advanced detection to different separation principles opens up the opportunity to critically evaluate the determination of molar masses and different types of radii for an in-depth understanding of the structural properties affected by the internal folding process. This is achieved by a detailed comparison of assets, drawbacks, and limitations of these approaches based on the systematical screening of different chain lengths and sizes of the precursors and the SCNPs. Furthermore, an alternative strategy for quantitative determination of intramolecular ligation density by a combination of AF4 and UV detection is introduced.

The design of chemiluminescent degradable particles is largely an unexplored field. We, herein, pioneer self-reporting chemiluminescent microspheres, allowing one to readily monitor their degradati...

We exploit the fluoride that is released via the para-fluoro-thiol reaction (PFTR) to cleave silyl ethers, turning the PFTR into an effective self-reporting chemiluminescence (CL) probe. The cleavage induces chemiluminescence and hence provides an optical read-out for the conversion of the PFTR. The PFTR chemiluminescence read-out is established on small molecule thiols, and subsequently expanded to polymers and networks.

The synthesis of single chain nanoparticles (SCNPs) is a vibrant field in macromolecular science, enabled by a rich variety of synthetic strategies to induce macromolecular chain folding. Due to the decrease of the hydrodynamic volume upon folding, SCNP formation is typically characterized by a shift towards higher elution volumes in size exclusion chromatography (SEC). However, a step-change in the methodologies for SCNP analysis is required for the in-depth understanding of the nature of intramolecular polymer folding and internal SCNP structure, which is critical to enable their application as catalytic nanoreactors. Herein, we exploit a unique combination of small-angle neutron scattering (SANS), 19F NMR spectroscopy, and quadruple detection SEC to generate an encompassing and systematic view of the folded morphology of poly(tert-butyl acrylate) based-SCNPs as a function of their reactive group density (5, 15, and 30 mol%) and absolute molar mass (20, 50, 100 kDa). In addition to detailed morphological insights, we establish that the primary factor dictating the compaction of SCNPs is their reactive group density, which is ineffective below 5 mol%, reaching maximum compaction close to 30 mol%. The molar mass of the precursor polymers has a minor impact on how an SCNP compacts for molar masses above 20 kDa.

The peroxyoxalate chemiluminescence (PO‐CL) reaction is among the most powerful and versatile techniques for the detection of hydrogen peroxide (H2O2) and has been employed in various biological and chemical applications over the past 50 years. However, its two‐component nature (peroxyoxalate and fluorophore) limits its use. This contribution introduces an innovative and versatile photochemical platform technology for the synthesis of inherently fluorescent PO probes by exploiting the nitrile imine‐mediated tetrazole‐ene cycloaddition (NITEC) reaction. In the presence of hydrogen peroxide, the pioneered “2‐in‐1” molecule emits either yellow or blue light, depending on tetrazole (Tz) structure. Even in the absence of base, the emitted light remains visible and H2O2 could be detected in the nanomolar range. Critically, the PO‐Tz can be readily incorporated into polymeric materials. As a first application of this promising material, a tailor‐made PO‐Tz is grafted on poly(divinylbenzene) (PDVB) particles to enable solid‐phase chemiluminescence on microspheres.

We introduce a protecting-group-free concept for the powerful para-fluoro-thiol reaction (PFTR) employing a source of fluoride ions as base. The reaction is shown to be self-propagating, with under-stoichiometric amounts of base, thus effectively foregoing the need for high base concentrations. Careful tuning of the solvent-thiol combination allows for quantitative conversion, in some cases within a short timeframe, when only minimal amounts of base are used, allowing the PFTR reaction to essentially proceed base-free.

A detailed kinetic study on the para-fluoro-thiol reaction (PFTR) using experimental analysis and kinetic Monte Carlo modeling is introduced, covering the difference in reactivity of a selected variety of structurally different thiols, uniquely including polymeric thiols. The impact of solvent polarity is evaluated by comparing the results obtained using THF and DMF, with the latter giving the fastest reaction rates. As PFTR involves the formation of a thiolate ion, potential side reactions such as disulfide bond formation are studied both isolated (determination of disulfide rate coefficients) and in competition with PFTR (determination of PFTR rate coefficients and selectivities). It is demonstrated that for star polymer synthesis – employing a polymeric thiol and a trifunctional fluorinated linker – the PFTR reacitivity is influenced by diffusional limitations and that the disulfide formation needs to be considered. Different reaction conditions (e.g. addition of reducing agent) are explored to limit the disulfide bond formation, providing the user a guideline for optimizing PFTR upon application for macromolecular design at high reaction rate.

We demonstrate that grafting a distribution of polymer chains onto an interface critically affects the shape of the distribution, with shorter chains being preferentially attached. This distortion effect is herein quantified for the first time, exploiting a quartz crystal microbalance – underpinned by single-molecule force spectroscopy – on the example of grafted poly(methyl methacrylate) (PMMA) chain distributions of different molar mass. ‘Grafting-to’ of different ratios of number average molecular weight of PMMA distributions unambiguously establishes the preferred surface grafting of shorter polymers, which can be correlated to their smaller radius of gyration. Our findings allow to establish a preferential grafting factor, k, which allows to predict the molar mass distribution of polymers on the surfaces compared to the initial distribution in solution. Our findings not only have serious consequences for functional polymer interface design, yet also for the commonly employed methods of grafting density estimation.

Bacterial biofilm formation on medical devices is a threat to healthcare systems worldwide as bacteria within a biofilm are more resistant to standard antimicrobial therapies. Herein, we introduce a nitroxide-based antibiofilm coating strategy, which is specifically designed to prevent biofilm formation of Gram-negative pathogens such as Pseudomonas aeruginosa. Nitroxide-decorated hydroxyapatite surfaces were readily prepared in an aqueous dip-coating procedure using a nitroxide-functionalized catecholamine as a polymerizable coating agent. Additional spatial control over the polymer surface deposition on titanium was gained by applying a photolithographic coating setup. All nitroxide-coated surfaces exhibited excellent antibiofilm properties toward PA14 surface colonization as biofilm formation was completely suppressed. Importantly, the surrounding adhesive polymer matrix did not interfere with the nitroxide-characteristic antibiofilm properties. The herein introduced platform technology represents a bioinspired and versatile coating approach, offering a safe and prophylactic avenue to combat biofilm contamination on a variety of surfaces.

We demonstrate that fluorescent, narrow-disperse microspheres are rapidly and readily prepared by photo-clicking pre-functionalised polymers using the highly efficient nitrile-imine mediated tetrazole-ene cycloaddition (NITEC) reaction. Our approach requires no stabilisers, bases or initiators, and proceeds under mild UV irradiation at ambient temperature. The diameter of the microspheres can be tuned in the 0.25–0.75 μm range depending on the reaction conditions, including polymer concentration, polymer ratio and the solvent composition. Critically, we explore the application potential of the microspheres, including fluorescence, degradation and swellability for encapsulation.

Green chemistry, sustainable chemistry, and circular chemistry are important concepts for the modern lifestyle, current research directions, and worldwide industries. These three concepts are closely related and interconnected but cannot be used synonymously. In addition, they are addressing two different economic models, i.e., linear economy and circular economy. The current contribution focuses on the importance of these decisive chemistries for the development of a sustainable future and their role in the realm of circular economy and the planetary boundaries framework—especially for the planetary boundary of “novel entities.” Researchers active in the field of polymer chemistry play an important role as plastic pollution and resource in addition to environmental depletion, caused by the still increasing production of polymers and plastics, become more and more pronounced. It is also reported that multi- and interdisciplinary approaches are needed to develop solutions for a sustainable future.

Herein, we introduce a comprehensive methodology to map the reactivity of photochemical systems on surfaces. The reactivity of photoreactive groups in solution often departs from their corresponding solution absorption spectra. On surfaces, the relationship between the surface absorption spectra and reactivity remains unexplored. Thus, herein, the reactivity of an o-methylbenzaldehyde and a tetrazole, as ligation partners for maleimide functionalized polymers, was investigated when the reactive moieties are tethered to a surface. The ligation reaction of tetrazole functionalized surfaces was found to proceed rapidly leading to high grafting densities, while o-methylbenzaldehyde functionalized substrates required longer irradiation times and resulted in lower surface coverage at the same wavelength (330 nm). Critically, wavelength resolved reactivity profiles were found to closely match the surface absorption spectra, contrary to previously reported red shifts in solution for the same chromophores.

The plastic economy, despite offering unique properties in fulfilling the functions of products in different industrial sectors over decades, has so far been mainly linear, that is, “take-make and dispose” with only a small fraction of plastics being recycled worldwide. With ever-increasing circular economy initiatives and the urge to conserve resources and prevent plastic pollution from affecting ecosystems, more emphasis on the resource recovery of plastic products after its use has been made over the last few years. It is necessary for manufacturers to understand the value chain as early as the design phase while manufacturing and distributing plastic products across the world. The current study provides an overview of the status quo of plastic waste management and analyzes the Life Cycle Assessment (LCA) studies of different End-of-Life (EoL) options for plastics. Based on the LCA studies, a preliminary, country-specific Circular Footprint (CF) is calculated and Design for Recycling (DfR) strategies are identified. Results show that the environmental impacts of different EoL options differ significantly for different plastics. The CF highlights the lack of data regarding the composition and recovery of plastics in different countries thus showing the necessity to consider the whole lifecycle when quantifying the environmental impacts of plastics.

We exploit the fluoride that is released via the para-fluoro-thiol reaction (PFTR) to cleave silyl ethers, turning the PFTR into an effective self-reporting chemiluminescence (CL) probe. The cleavage induces chemiluminescence and hence provides an optical read-out for the conversion of the PFTR. The PFTR chemiluminescence read-out is established on small molecule thiols, and subsequently expanded to polymers and networks.

Polymers and plastics play a very important part in the modern world and contribute to people's wellbeing and comfort. However, products made of them are contributing to land- and marine-based environmental pollution due to littering and other ways of emission, and therefore threaten ecosystems worldwide. However, waste management and responses by governments and the consumer differ strongly from country to country. The current article provides an overview of several important aspects of polymer waste and plastic pollution as well as describes selected strategies to mitigate these using examples from Germany and Australia, and therefore aims to contribute to the resolution of the ever-increasing problem of unsustainable plastic consumption, disposal, and pollution.

The formation of single chain nanoparticles (SCNPs) is typically characterized by a shift towards higher elution volumes in SEC due to size decrease upon folding. However, a step-change in SCNP analysis is required for understanding of the nature of intramolecular SCNP folding. Herein, we exploit a unique combination of SANS, 19F NMR spectroscopy, and multidetection SEC to generate a systematic view of the folded morphology of poly(butyl acrylate) based-SCNPs as a function of their reactive group density and molar mass. In addition to detailed morphological insights, we establish that the primary factor dictating the compaction of SCNPs is their reactive group density, which is ineffective below 5 mol%, reaching maximum compaction close to 30 mol%. Above 20 kDa the molar mass of the precursor polymers has a minor impact on how an SCNP compacts.

Herein, we introduce a fast, additive-free, ambient temperature photochemical approach – utilising the novel Diels–Alder cycloaddition of a photo-active ortho-methylbenzaldehyde (oMBA) with a terminal alkyne – for preparing functional acid-sensitive profluorescent nano-/microspheres in one step. Not previously reported, the possibility of applying such a reaction in the context of particle synthesis provides new possibilities for particle design, where multi-step reactivity can be gated into distinct steps. First, a photochemically-gated particle formation step yields a material possessing a reactive, spring-loaded intermediate at every cross-linking point. A second, on-demand step to initiate fluorescence generation subsequently imparts the properties of the chemical transformation to the material itself. The synthesised particles are narrow-disperse with an average diameter ranging from 170–380 nm.

Surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization was used to synthesize poly(methyl methacrylate) (PMMA) and poly[2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammoniumhydroxide (PMEDSAH) brushes grafted from reactive poly[p-xylylene] surfaces. The synthetic approach involved functionalization of substrates via chemical vapor deposition polymerization of an electron-deficient alkynyl-functionalized [2.2]paracyclophane derivative. An azide-functionalized RAFT agent was anchored to the resulting poly[(p-xylylene-4-methyl propiolate)-co-p-xylylene] films via copper-free click-chemistry. Subsequent SI-RAFT polymerization yielded PMMA and PMEDSAH films with narrow dispersity which was further tuned by varying the concentration of a sacrificial RAFT agent in solution. Polymer dispersity was determined by size exclusion chromatography to be in the range of 1.2–1.4 for both polymers. This work provides a novel surface modification strategy to decorate a wide range of different substrates with polymer brushes, thereby eliminating the need for cumbersome modification protocols, which so far had to be established for each substrate material independently.

We introduce a fluorescence-based methodology enabling the quantification of ligation points in photochemically prepared polymer networks. Well-defined α,ω-tetrazole-capped polymer strands prepared via RAFT polymerization are crosslinked under UV irradiation by a trimaleimide via nitrile imine mediated tetrazole-ene cycloaddition. Thus, for each linkage point a fluorescent pyrazoline ring is formed, resulting in fluorescent networks, which are degradable by aminolysis of the trithiocarbonate functionalities, leading to soluble fragments. The fluorescence emission of the soluble network fragments correlates directly with the number of pyrazoline moieties originally present in the network, thus providing a direct measure of the number of ligation points constituting the network. The herein introduced strategy based on a fluorescence readout is a powerful yet simple approach to quantify network formation processes applicable to a wide class of polymers accessible via RAFT.

We pioneer a versatile surface modification strategy based on mussel-inspired oxidative catecholamine polymerization for the design of nitroxide-containing thin polymer films. A 3,4-dihydroxy-l-phenylalanine (l-DOPA) monomer equipped with a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-derived oxidation-labile hydroxylamine functional group is employed as a universal coating agent to generate polymer scaffolds with persistent radical character. Various types of materials including silicon, titanium, ceramic alumina, and inert poly(tetrafluoroethylene) (PTFE) were successfully coated with poly(DOPA-TEMPO) thin films in a one-step dip-coating procedure under aerobic, slightly alkaline (pH 8.5) conditions. Steadily growing polymer films (∼1.1 nm h–1) were monitored by ellipsometry, and their thicknesses were critically compared with those obtained from atomic force microscopic cross-sectional profiles. The heterogeneous composition of surface-adherent nitroxide scaffolds examined by X-ray photoelectron spectr...

In the current contribution, we discuss the application and potential of the versatile para-fluoro-thiol reaction in the context of synthesis and modification of polymers and materials made thereof. General reaction parameters such as solvent, temperature, and activator are reviewed. In addition, orthogonality towards some important ligation methods is examined. A brief description of the applications in which the PFTR was employed is finally provided. We postulate that the PFTR will come to be increasingly considered as a powerful complement to well-established coupling methodologies, due to the generally high selectivity of pentafluorophenyl moieties towards thiols under mild, metal-free conditions.

We introduce the preparation and ring-opening polymerization of a nitroxide containing carbonate monomer. Using 1,8-diazabicyclo undec-7-ene (DBU) and a thiourea as the catalyst system, we demonstrate that the free radical moiety of the monomer has no influence on the ring-opening copolymerization with D/L-lactide in a wide range of compositions between 10% and 80% of the nitroxide monomer, which can be readily controlled by the comonomer composition in the polymerization mixture. The copolymers exhibit narrow and monomodal mass distributions with number average molar masses between 6000 g·mol −1 to 7000 g·mol −1 and low dispersities below 1.1. The free radical functionality is retained during the polymerization as demonstrated by electron spin resonance (EPR) spectroscopy. High-resolution mass spectrometry coupled to size exclusion chromatography allowed an in-depth analysis of the copolymers showing well-defined linear polymer chains with excellent endgroup fidelity. Furthermore, the molar mass of the polymers was controlled by the monomer to initiator ratio which led to copolymers of up to 19 500 g·mol −1 .

We pioneer the design of dual-gated microparticles, both responsive to changes in temperature and pH, for stimuli-responsive chromatography targeted at the efficient separation of antibodies. Dual-gated microspheres were synthesized by introducing RAFT-based thiol-terminal block copolymers of poly(N-isopropylacrylamide-b-4-vinylpyridine) (P(NIPAM-b-4VP, 4800 ≤ Mn/Da ≤ 10 000, featuring block length ratios of 29:7, 29:15, and 29:30, respectively) by thiol-epoxy driven ligation to the surface of poly(glycidyl methacrylate) (PGMA) microparticles (10–12 μm), whereby the 4-vinylpyridine units within the lateral chain enable protein binding. The switchable protein release abilities of the resulting microparticle resins are demonstrated by adsorption of immunoglobulins at 40 °C and pH 8 and their release at 5 °C or pH 3, respectively. We demonstrate that P(NIPAM29-b-4VP30)-grafted PGMA particles show a maximum adsorption capacity for immunoglobulins of 18.9 mg mL–1 settled resin at 40 °C/pH 8, whereas the adsorp...

We introduce the regioselective para-fluoro-thiol reaction (PFTR) as a novel strategy for network formation. Here, a novel fluorinated linker is designed and further reacted with several bifunctional thiols to demonstrate the versatility of the method. Critically, the formation of the networks is evidenced by XPS and ToF-SIMS.

We introduce the high-resolution electrospray ionization mass spectrometric (ESI MS) structural elucidation of polymerized 3,4-dihydroxy-L-phenylalanine (L-DOPA) carrying 1-methoxy-2,2,6,6-tetramethylpiperidin-4-amide groups in the side chain. Critically, our powerful ESI MS platform unambiguously revealed the structurally diverse character of this multifunctional bio-adhesive polymer system.

A series of poly(sodium methacrylate) hydrogels, also called superabsorbents, having a theoretical degree of neutralization of 100 mol%, and degree of crosslinking varying from 0.6 to 20 mol%, are synthesized via conventional free radical polymerization. The networks are characterized in detail by inverse size-exclusion chromatography and 1H-NMR relaxometry in order to place particular emphasis on the investigation of the pore size distribution (PSD) and the chain mobility, respectively. The two previously mentioned parameters are compared to understand the correlation between the elastic chain mobilities and the average pore size of the hydrogel. From the resulting data, a new empirical equation is proposed, which is valid under the given experimental conditions and permits a rough estimation of the average PSD from the relaxation data. Thus, the equation permits to reduce the number of analytical techniques needed for the characterization of complex systems such as polymer networks.

International audience; We introduce recodable surfaces solely based on reversible artificial hydrogen bonding interactions. We show that a symmetrical oligoamide (SOA) attached to poly(methyl methacrylate) (PMMA) can be repeatedly immobilized and cleaved off spatially defined surface domains photochemically functionalized with asymmetric oligoamides (AOAs). The spatially resolved recodability is imaged and quantified via ToF-SIMS.

A substrate‐independent and versatile coating platform for (spatially resolved) surface functionalization, based on nitroxide radical coupling (NRC) reactions and the formation of thermo‐labile alkoxyamine functional groups, was introduced. Nitroxide‐decorated poly(glycidyl methacrylate) (PGMA) microspheres, obtained through bioinspired copolymer surface deposition using dopamine and a nitroxide functional dopamine derivative as monomers, were conjugated with small functional groups in a rewritable process. Reversible coding of the nitroxide functional microspheres by NRC and decoding through thermal alkoxyamine fission were monitored and characterized by electron paramagnetic resonance (EPR) spectroscopy and X‐ray photoelectron spectroscopy (XPS). In addition, this nitroxide coating system was exploited in “grafting‐to” polymer surface ligations of poly(methyl methacrylate) (PMMA) and poly(2,2,2‐trifluoroethyl methacrylate) (PTFEMA) in spatially confined areas. Polymer strands terminated with an Irgacure 2959 (2‐hydroxy‐4′‐(2‐hydroxyethoxy)‐2‐methylpropiophenone) photoinitiator were obtained through chain‐transfer polymerization, and subsequently coupled to nitroxide‐immobilized poly(dopamine) (PDA)‐coated silicon substrates by using rapid photoclick NRC reactions. Light‐driven polymer surface coding was visualized by time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and XPS imaging.

An in-depth investigation of the network topology for a series of sodium acrylate hydrogels synthesized via conventional free radical polymerization (FRP) and reversible addition–fragmentation chain transfer (RAFT) polymerization is conducted. The role of the RAFT agent on the crosslinking process is demonstrated on a model system upon analysis of the reaction mixture via size-exclusion chromatography before the gelation point. For a comprehensive study, both the impact of the amount of RAFT agent and of the degree of crosslinking on the microstructure of the final product are systematically investigated. In addition to swelling experiments and oscillatory shear rheology measurements, the resulting networks are analyzed via low-field proton nuclear magnetic resonance (1H-NMR) techniques such as transverse relaxation and double-quantum coherence to evaluate the network mobility, which is then correlated to structural inhomogeneity. A broader mobility distribution is observed for the RAFT mediated networks compared to the FRP samples, which can be assigned to a higher content of dangling ends in the former case. The results are further elaborated to propose a mechanism for network formation in presence of a RAFT agent. Special Issue: 100 Years of Macromolecular Chemistry and Physics

The synthesis of crosslinked polymeric microspheres (3.8-15.0 µm) via (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) initiated thiol-ene dispersion polymerization under ambient conditions is reported for the first time. The initiating ability of TEMPO for the thiol-ene reaction is validated by electron paramagnetic resonance (EPR) and 1 H nuclear magnetic resonance (NMR) spectroscopy on model reactions between 1-octadecanethiol and two electron deficient enes, n-butylacrylate and divinyl sulfone. Critically, the TEMPO resonance observed in the EPR spectra decreases with time when TEMPO is mixed with thiol and an electron deficient ene. The 1 H NMR spectra demonstrate formation of up to 90% of thioether under ambient conditions. Based on these model reactions, a variety of crosslinked polymeric microspheres are synthesized with excellent morphological stability using poly(vinyl pyrrolidone) as surfactant. The ability of the microspheres for a second TEMPO initiated thiol-ene reaction is demonstrated by the ligation of fluorescein-5-maleimide (an ene) to the microspheres' surface containing excess of thiol functionality and by ligation of cysteine (containing a thiol group) to the microspheres' surface containing an excess of ene functionality. The synthesized polymeric microspheres are characterized using scanning electron microscopy, differential scanning calorimetry, Fourier-transform infrared spectroscopy, zeta potential, and X-ray photoelectron spectroscopy.

A general synthetic strategy is described that enables access to a library of new sulfobetaine methacrylates starting from commercially available precursors. The three-step procedure allows the distance between the quaternary amine and the sulfonate group (inner charge distance) to be varied by selecting the corresponding dibromoalkane in the first step. A key step is the final esterification, in which methacrylic acid acts as solvent as well as reagent for the zwitterionic hydroxy intermediates. Thus, it is possible to synthesize monomeric precursors with up to twelve methylene groups between the positive and the negative charge. A selection of these monomers has been successfully tested for their ability to polymerize using free-radical polymerization.

In the current study, well-defined polymer brushes are shown as an effective surface modification to resist biofilm formation from opportunistic pathogens. Poly[oligo(ethylene glycol)methyl ether methacrylate] (poly(MeOEGMA)) and poly[N-(2-hydroxypropyl)methacrylamide] (poly(HPMA)) brushes were grown by surface initiated atom transfer radical polymerization (SI-ATRP) and subsequently characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and dynamic water contact angle measurements. Their remarkable resistance to protein fouling after long term contact with biological media was evidenced by surface plasmon resonance spectroscopy. Challenging these brushes with an environmental strain of Pseudomonas aeruginosa in mineral media as well as a casein–soja–pepton–agar (CASO) medium resulted in no biofilm formation, while a decrease of the biofilm formation by 70% (poly(HPMA)) and 90% (poly(MeOEGMA)) was observed when the medium was rich in nutrients and proteins (fetal bovine serum). In contrast to the antibiotic sensitive strains, biofilm formation was observed using an antibiotic multi-resistant P. aeruginosa strain on both brushes. Protein fouling was fully prevented on both types of brushes, which might challenge the proposed mechanism of biofilm formation mediated by a pre-formed conditioning film of proteins. The resistance to biofilm formation and the possibility to precisely control their growth and functionalities makes these brushes ((poly(HPMA) and (poly(MeOEGMA)) promising candidates for surface modification of various biomaterials as well as platforms for basic studies into the mechanisms of bacteria fouling.

A new strategy for particle synthesis is enabled by utilizing modern synthetic, polymer, and photochemical techniques to facilitate the synthesis of highly narrow–disperse multifunctional microspheres from visible-light induced crosslinking of prepolymers in both a single and dual polymer system. The approach requires no stabilizers, bases, or initiators, and proceeds at ambient temperature to yield microspheres with a tunable size range (0.25–5 µm) in less than 4 h, depending largely on solvent composition, but also polymer concentration (2–10 mg mL−1), ratio, and irradiation intensity (3–20 W). Critically, the visible-light induced dimerization reaction exploited herein enables simple functional particle syntheses via a single polymer system. Underpinned by an in-depth kinetic analysis of the particle formation as well as a detailed small molecule study, the mechanism for particle formation is also elucidated. Importantly, inherent advantages of the system are exploited for surface functionalization of residual acrylate and hydroxyl groups (generating inherently fluorescent particles).