Vapor Swelling of Polymer Brushes Compared to Nongrafted Films

Eck, Guido C. Ritsema van; Kiens, Ellen Marijn; Veldscholte, Lars B.; Pérez, Maria Brió; Beer, Sissi de

doi:10.1021/acs.langmuir.2c01889

Cited by 4 publications

(5 citation statements)

References 48 publications

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“…The (equilibrium) swelling ratios exhibit a strong superlinear relation with the humidity, in accordance with previous studies [36]; at low humidity (< 60%), there is barely any swelling, while above that, small changes in humidity result in large changes in swelling. For these higher humidities, an equilibrium is not fully reached within the 90 s timeframe of the measurement.…”

Section: Ellipsometrysupporting

confidence: 92%

“…Polymer brushes exhibit properties that can be considerably different from nongrafted films or bulk polymers [23,24], which gives rise to a broad range of applications in the (bio-)medical field [25,26] in anti-fouling surfaces [27,28], lubricious surfaces [29,30], sensors [31] and separation membranes [32,33]. In several of these applications, brushes are swollen by vapours [34], such as water [35,36]. Understanding brush swelling dynamics is imperative for proper application of brushes in these contexts.…”

Section: Introductionmentioning

confidence: 99%

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Millisecond-resolved infrared spectroscopy study of polymer brush swelling dynamics

Jorissen,

Veldscholte,

Odijk

et al. 2024

Meas. Sci. Technol.

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We present the study of millisecond-resolved polymer brush swelling dynamics using infrared spectroscopy with a home-built quantum cascade laser-based infrared spectrometer at a 1 kHz sampling rate after averaging. By cycling the humidity of the environment of the polymer brush, we are able to measure the swelling dynamics sequentially at different wavenumbers. The high sampling rate provides us with information on the reconformation of the brush at a higher temporal resolution than previously reported. Using spectroscopic ellipsometry, we study the brush swelling dynamics as a reference experiment and to correct artefacts of the infrared measurement approach. This technique informs on the changes in the brush thickness and refractive index. Our results indicate that the swelling dynamics of the polymer brush are poorly described by Fickian diffusion, pointing toward more complicated underlying transport.

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Section: Ellipsometrysupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Millisecond-resolved infrared spectroscopy study of polymer brush swelling dynamics

Jorissen,

Veldscholte,

Odijk

et al. 2024

Meas. Sci. Technol.

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“…While spun-cast films are expected to show different water absorption as compared to the grafted brush, the reported differences are small and may not largely affect the glass transition humidity. [27,39] In this case, we observe the same high-tolow shear force transition past RH g just like that for the grafted brush, which occurs at a similar %RH. This observation confirms that the friction trend is closely related to the humidity-induced glass transition rather than anything specific about the brush architecture, providing support for the argument that this may be a much more general phenomenon.…”

Section: Extension Of Friction Transition To Similar Systemssupporting

confidence: 69%

“…Although, prior studies considering polyelectrolyte brush water uptake in humid vapor generally have not considered the possibility of such a transition, possibly due to the continuous nature of the observed water absorption. [28,29,38,26,39] Yet, a glass transition could itself have implications on the properties of a brush beyond just the water uptake due to the mechanical properties and chain relaxation dynamics that can change rapidly. [40,41] Despite this outstanding knowledge gap and potential applications, no research work to date has examined in detail how the water absorption behavior of a polyelectrolyte brush with humidity affects properties such as friction.…”

Section: Introductionmentioning

confidence: 99%

Switchable Slippery Surfaces Controlled by a Humidity‐Induced Glass Transition of Polyelectrolyte‐Grafted Brushes

Merriman,

Singla,

Dhinojwala

2024

Adv Materials Inter

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Polymer brushes have found extensive applications as nano‐scale surface coatings with responsive properties, particularly in achieving tunable friction in solvent environments. Here, a special property of hygroscopic polyelectrolyte‐grafted brushes, where the friction forces change by over two orders of magnitude within a narrow range in humidity is reported. Using mechanical measurements of nano‐scale modulus and water absorption coupled with friction and surface‐sensitive spectroscopy, this sharp change in friction is controlled by a humidity‐induced glass transition that abruptly shifts the mode of sliding is demonstrated. Contrary to expectations based on conventional thinking regarding brush lubrication, friction remains large and humidity‐independent below the glass transition even for systems that absorb as much as 30–40% water by volume. This results in an abrupt change in friction past the glass transition humidity. Tuning the chemistry of brushes and their humidity‐induced glass transition offers the tunability to control the on/off friction (or slipperiness) for nanoactuators, ratchets, and catheters, without the need for externally applied lubricating liquids.

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“…That polymer brushes adsorb solvent vapors is indeed known. [13] Khatir and Golovin commented that the same reduction in contact angle hysteresis can be explained simply by a change in γ LV , γ SV , and γ SL . [14] As a result, the force balance at the contact line and the contact angles change.…”

mentioning

confidence: 97%

Response to Comment on “Vapor Lubrication for Reducing Water and Ice Adhesion on Poly(dimethylsiloxane) Brushes”: Organic Vapors Influence Water Contact Angles on Hydrophobic Surfaces

Butt

2023

Advanced Materials

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widely used, little research has been carried out to analyze the effect of the vapor. Boyd and Livingston [2] in 1942, and later Ward and Wu [3] in 2007 pointed out that the adsorption of vapor to the free solid surface is supposed to change contact angles because of the reduction in γ SV . In 1988, Yekta-Fard and Ponter [4] measured no change in water contact angles of water drops on Teflon when they are exposed to the vapor of cyclohexane, decane, or undecane. Several authors [5] studied the change of the surface tension of water due to the adsorption of organic vapors.In many natural phenomena and industrial applications, the sliding of drops on surface is important, such as coating, [6] energy conversion, [7] and water harvesting, [8] or for glasses or windscreens in rain. In these cases, one needs to discriminate between advancing θ a and receding contact angles θ r . The difference between the two is called contact angle hysteresis. It can be caused by surface heterogeneity, roughness, or adaptation. [9] Contact angle hysteresis is important because it determines the friction force of sessile drops: F = kγ LV w(cosθ r − cosθ a ). [2,10] Here, k ≈ 1 is a shape factor and w is the width of the contact area between drop and solid surface.Despite remarkable developments, the mechanism for drop mobility on surfaces is far from being understood nor controlled. In this respect, surfaces coated with poly(dimethylsiloxane) (PDMS) brushes have attracted great interest because of their low contact angle hysteresis. [11] In a recent paper, we demonstrated that the contact angle hysteresis of water drops on PDMS-coated surfaces is further reduced, when the system is exposed to toluene vapor. [12] We explained the effect by the lubricating action of the vapor being adsorbed in the PDMS layer. This hypothesis was supported by an increase of layer thickness in toluene vapor detected by atomic force microscopy. That polymer brushes adsorb solvent vapors is indeed known. [13] Khatir and Golovin commented that the same reduction in contact angle hysteresis can be explained simply by a change in γ LV , γ SV , and γ SL . [14] As a result, the force balance at the contact line and the contact angles change. It is indeed known, that when exposing water to the vapor of an organic liquid,

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Vapor Swelling of Polymer Brushes Compared to Nongrafted Films

Cited by 4 publications

References 48 publications

Millisecond-resolved infrared spectroscopy study of polymer brush swelling dynamics

Millisecond-resolved infrared spectroscopy study of polymer brush swelling dynamics

Switchable Slippery Surfaces Controlled by a Humidity‐Induced Glass Transition of Polyelectrolyte‐Grafted Brushes

Response to Comment on “Vapor Lubrication for Reducing Water and Ice Adhesion on Poly(dimethylsiloxane) Brushes”: Organic Vapors Influence Water Contact Angles on Hydrophobic Surfaces

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