Evidences for charged hydrogen bonds on surfaces bearing weakly basic pendants: The case of PMMA–ran–PDMAEMA polymeric films

Mella, Mariella; Tagliabue, Andrea; Vaghi, Stefano; Izzo, Lorella

doi:10.1016/j.colsurfa.2021.126525

Cited by 8 publications

(5 citation statements)

References 66 publications

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“…Our results pave the way toward attaining a broader and finer external tunability of polymer properties by considering additional solvent- or solution-dependent features as well as the overall chain length. The latter may include the degree of solvophilicity of monomers belonging to different blocks or the presence of chemical specific interactions between monomers − or with mobile ions. , For instance, a lower solvophilicity of short alternating blocks, or strong hydrogen bonding, may pin one or more essential crossings, thus impacting the contour mobility of the knot . An alternative way to achieve such effect would be to confer weak acid and basic properties to different chain segments, obtaining polyampholytes with switchable (e.g., by means of pH stimuli) interblock interactions and possibly different effective block rigidities .…”

Section: Discussionmentioning

confidence: 99%

Tuning Knotted Copolyelectrolyte Conformations via Solution Properties

2022

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We used Langevin dynamics simulations to study coarse-grained knotted copolyelectrolytes, composed by a neutral and a charged segment, in solutions of different salt concentrations, valency, and solvent screening power. We show that the facile variation of these parameters allows for tuning the length and position of the knotted region, which in turn controls the overall metric properties. Specifically, adding either monovalent or divalent ions causes the knot to swell at the expense of the copolyelectrolyte overall size. However, the knot typically straddles the charged–neutral interface in the presence of monovalent counterions, whereas it is attracted on the charged segment with divalent ones. Notably, similar modulations of knot size and position can also be achieved by varying the dielectric constant of the solvent. Our results demonstrate the feasibility of harnessing the solution-mediated balance of electrostatics and conformational entropy toward a facile external tuning of the conformational properties of knotted polymers.

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Section: Discussionmentioning

confidence: 99%

Tuning Knotted Copolyelectrolyte Conformations via Solution Properties

2022

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“…Spin-coated samples were closed within plastic Petri dishes and placed under a chemical hood for 20 h at room temperature to evaporate completely CHCl 3 from the fluid film. Once dried, ultrathin films are solid, transparent, and insoluble (in water) [22].…”

Section: Preparation Of Ultrathin Polymeric Films By Spin-coatingmentioning

confidence: 99%

“…Ultrathin and thick polymeric films were prepared by drop-casting [30] and casting [22], respectively. Ultrathin films drop-casted, ≈20 nm thick, were obtained by depositing 1 mL of solution on a TEM grid (mesh 300) placed on the CMP substrate.…”

Section: Preparation Of Ultrathin and Thick Polymer Films By Drop-cas...mentioning

confidence: 99%

Morphology and Mechanics of Star Copolymer Ultrathin Films Probed by Atomic Force Microscopy in the Air and in Liquid

Albonetti,

Izzo,

Vigliotta

et al. 2024

Materials

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Star copolymer films were produced by using spin-coating, drop-casting, and casting deposition techniques, thus obtaining ultrathin and thick films, respectively. The morphology is generally flat, but it becomes substrate-dependent for ultrathin films where the planarization effect of films is not efficient. The indentation hardness of films was investigated by Force Volume Maps in both the air and liquid. In the air, ultrathin films are in the substrate-dominated zone and, thus, the elastic modulus E is overestimated, while E reaches its bulk value for drop-casted ultrathin and thick films. In liquid (water), E follows an exponential decay for all films with a minimum soaked time t0 of 0.37 and 2.65 h for ultrathin and drop-casted ultrathin and thick films, respectively. After this time, E saturates to a value on average 92% smaller than that measured in the air due to film swelling. Such results support the role of film morphology in the antimicrobial activity envisaged in the literature, suggesting also an additional role of film hardness.

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“…Obviously, the linear relationship λ = pH – p K a easily allows one to recast eq in terms of λ. We have previously used such quantity to characterize polyelectrolytes energetics and adsorption spontaneity in several circumstances. ,,,,, As for gauging the impact on the systems Helmholtz energy due to c-H-bond formation, we recall that the chosen analytical form for the c-H-bond potential is indeed linear in the well depth ζ (see discussion in section ), a fact that allows one a fairly easy estimate . In our specific case, it is convenient to exploit thermodynamic integration, increasing the well depth from zero to ζ * to compute Δ MB A (ζ * ) = ∫ 0 ζ * ⟨ e (ρ)⟩ ζ d ζ , with ⟨ e (ρ)⟩ ζ being the average number of c-H-bonds.…”

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confidence: 99%

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Impact of Chemically Specific Interactions between Anions and Weak Polyacids on Chain Ionization, Conformations, and Solution Energetics

Mella

Tagliabue

2022

Macromolecules

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The presence of salts in a solution containing weak polyelectrolytes is known to modify both their titration behavior and conformations due to electrostatic screening. Instead, little is currently known about the changes induced by chemically specific interactions (e.g., charged hydrogen bonds, c-H-bonds). To investigate this aspect, we simulated the titration of weak polyacids with a primitive model and Monte Carlo methods in the presence of monovalent salts whose anions are capable of forming c-H-bonds with associated acid groups. The interaction between anions and weak polyacids (e.g., poly(acrylic acid)) substantially hampers ionization at low pH despite the somewhat limited number of coordinated anions, whereas it has a limited impact once pH > pK a + 2 due to a progressive anion decoordination. Importantly, the suppression of ionization appears extremely local in nature, with different chain segments differing in pK a by up to 1.3 units. As for chain conformations, c-H-bonds reduce the average sizes of polyacids independently of their structure as a consequence of multidentate binding or multiarm coordination in starlike species. Analyzing the length of chain segments with all monomers coordinated or uncoordinated has also evidenced that anion binding is extremely local in nature. The energetic analysis of c-H-bond formation suggests that polyacid chemical potential may be strongly lowered (up to −0.7 kcal/mol per monomer), the impact of such results on a few phenomena relevant for the physical chemistry of polyacid-containing solutions being analyzed in some detail.

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Evidences for charged hydrogen bonds on surfaces bearing weakly basic pendants: The case of PMMA–ran–PDMAEMA polymeric films

Cited by 8 publications

References 66 publications

Tuning Knotted Copolyelectrolyte Conformations via Solution Properties

Tuning Knotted Copolyelectrolyte Conformations via Solution Properties

Morphology and Mechanics of Star Copolymer Ultrathin Films Probed by Atomic Force Microscopy in the Air and in Liquid

Impact of Chemically Specific Interactions between Anions and Weak Polyacids on Chain Ionization, Conformations, and Solution Energetics

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