Tailoring the Attraction of Polymers toward Surfaces

Stein, Gila E.; Laws, Travis S.; Verduzco, Rafael

doi:10.1021/acs.macromol.9b00492

Cited by 57 publications

(67 citation statements)

References 159 publications

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“…[ 30 ] This behavior is enhanced in branched systems, including dendritic, where the number of chain‐ends is high. Additionally, entropically‐driven chain‐end surface segregation has been theoretically predicted [ 31–33 ] and experimentally shown [ 34–36 ] to induce surface wettability reversal, in which high energy components occupy the material surface. Thus, the strategic placement of antimicrobials on branched chain‐ends could result in a physically bound additive with surface active behavior.…”

Section: Figurementioning

confidence: 99%

Synthesis and Characterization of Cationic Dendrimer‐PDMS Hybrids

Marks

Kalaitzidou

Gutekunst

2020

Macromol. Rapid Commun.

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A modular strategy for the synthesis of dendron‐linear polymer hybrids comprised of a flexible polydimethylsiloxane (PDMS) midblock with cationic 2,2‐bis(hydroxymethyl)propionic acid (bis‐MPA) dendron end groups is developed. The invention of a scalable methodology to access quaternary ammonium carboxylate building blocks and their direct use in esterification chemistry enables rapid access to cationic bis‐MPA dendrons. The convergent click coupling of highly charged dendrons to hydrophobic PDMS chain‐ends gives a 12‐membered family of hybrids that are comprised of different dendron generations (G1–3) and quaternary ammonium alkyl chain lengths (C4, C8, C12, C16). This provides a library of materials with variable hydrophobicity, charge density, and chain‐end valency. The physical behavior of the dendron‐linear PDMS hybrid copolymers significantly changes after introduction of the cationic dendron end‐groups and leads to soft‐solid materials as a result of inhibited chain mobility. These PDMS‐dendron hybrids are expected to behave as surface‐active antimicrobial additives in bulk cross‐linked silicone systems.

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Section: Figurementioning

confidence: 99%

Synthesis and Characterization of Cationic Dendrimer‐PDMS Hybrids

Marks

Kalaitzidou

Gutekunst

2020

Macromol. Rapid Commun.

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“…Taking inspiration from these observations, films of PLA/CA and PLA/MDCA5 are hot melted at 180 °C between aluminum and Teflon sheets. The surface energy of aluminum is 39.5 mJ/m 2 , that of Teflon is 13.6 mJ/m 2 [ 44 ], and that of PLA is 42 mJ/m 2 [ 45 ]. CA has a polar group, and for this reason, it is expected that its migration is favored towards aluminum rather than towards Teflon that has a lower surface energy.…”

Section: Resultsmentioning

confidence: 99%

Macromolecular Dyes by Chromophore-Initiated Ring Opening Polymerization of L-Lactide

et al. 2020

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End functionalized polylactides are prepared by ring opening polymerization of L-lactide in the presence of stannous octoate (Sn(Oct)2). Three chromophores, 9H-carbazol-ethanol (CA), 9-fluorenyl-methanol (FM), and 2-(4-(2-chloro-4-nitrophenylazo)-N-ethylphenylamino)ethanol (Disperse Red 13, DR), are for the first time used as co-initiators in the polymerization process. The polymerization reaction is initiated by conventional thermal treatment, but in the case of FM, microwave-assisted polymerization is also carried out. CA and FM absorb and emit in the UV portion of the electromagnetic spectrum, whereas DR absorbs in the visible part. The obtained end-capped polylactides derivatives show the same photophysical properties as the initiator, so they are “macromolecular dyes” (MDs) that can be used “as synthesized” or can be blended with commercial poly(lactic acid) (PLA). The blends of PLA with MDs have ultraviolet-visible (UV-Vis) absorption and fluorescence emission features similar to that of MDs and thermal properties typical of PLA. Finally, migration tests, carried out onto the blends of PLA with MDs and PLA with free chromophores, show that MDs are less released than free chromophores both in solution and in the solid phase.

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“…The segregation of the chain end to the solid surface with no specific chemical interactions provides the minimization loss of conformational entropy at the interface [42,43]. Both SSP and PPP spectra of [N888H][DEHP] and [P8888] [DEHP] show three peaks at ~2850 cm −1 , 2870 cm −1 , and 2940 cm −1 , and the previous study has shown that the charged head groups of these IL molecules are preferentially interacting with the silica surface while their alkyl chains facing the bulk liquid (Figure 5b) [11,43]. The SSP spectrum of OFM has a very weak signal at ~2850 cm −1 (this peak was not captured well in the spectral fitting) while its relative intensity at ~2950 cm −1 (CH2,s,FR or CH2,as of C-CH2-O) is very strong.…”

Section: Sfg Spectra Of Individual Compounds At Silica/liquid Interfacementioning

confidence: 99%

Competitive Adsorption of Ionic Liquids Versus Friction Modifier and Anti-Wear Additive at Solid/Lubricant Interface—Speciation with Vibrational Sum Frequency Generation Spectroscopy

Ngo

Luo

et al. 2020

Lubricants

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A modern lubricant contains various additives with different functionalities and the interactions or reactions between these additives could induce synergistic or antagonistic effects in tribological performance. In this study, sum frequency generation (SFG) spectroscopy was used to investigate competitive adsorption of lubricant additives at a solid/base oil interface. A silica substrate was used as a model solid surface. The lubricant additives studied here included two oil-soluble ionic liquids (ILs, [N888H][DEHP] and [P8888][DEHP]), an antiwear additive (secondary ZDDP), an organic friction modifier (OFM), and a dispersant (PIBSI). Our results showed that for mixtures of ZDDP and IL in a base oil (PAO4), the silica surface is dominated by the IL molecules. In the cases of base oils containing OFM and IL, the silica/lubricant interface is dominated by OFM over [N888H][DEHP], while it is preferentially occupied by [P8888][DEHP] over OFM. The presence of PIBSI in the mixture of PAO4 and IL leads to the formation of a mixed surface layer at the silica surface with PIBSI as a major component. The SFG results in this investigation provide fundamental insights that are helpful to design the formulation of new lubricant additives of desired properties.

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Tailoring the Attraction of Polymers toward Surfaces

Cited by 57 publications

References 159 publications

Synthesis and Characterization of Cationic Dendrimer‐PDMS Hybrids

Synthesis and Characterization of Cationic Dendrimer‐PDMS Hybrids

Macromolecular Dyes by Chromophore-Initiated Ring Opening Polymerization of L-Lactide

Competitive Adsorption of Ionic Liquids Versus Friction Modifier and Anti-Wear Additive at Solid/Lubricant Interface—Speciation with Vibrational Sum Frequency Generation Spectroscopy

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