Water Diffusion in Polymer Composites Probed by Impedance Spectroscopy and Time-Resolved Chemical Imaging

ACS Appl. Polym. Mater.

Bingöl

et al. 2020

Self Cite

Maintaining adhesion on human skin during perspiration is challenging and may result in undesired detachment. Improvements in the performance are generally made by adjustments in the adhesive composition, which simultaneously changes the viscoelastic properties, sweat absorption capabilities, and peel adhesion. To aid the design of skin adhesives for prolonged wear, we systematically investigate the impact of the viscoelastic properties and the sweat absorption capabilities during perspiration. Therefore, four skin adhesives are designed with a stepwise variation in one of the properties at a time to decouple the different effects. A perspiration simulator is used during the study to ensure well-defined and reproducible perspiration conditions. Depending on the sweating pressure and the adhesive formulation, different failure mechanisms are observed. The sweating pressure delaminates the non-absorbing adhesives and causes adhesive failure. Thereby, viscoelastic flow and subsequent cavity growth occur if the sweating pressure overcomes the mechanical strength of the adhesive, while elastic detachment is observed otherwise. The addition of absorbing components results in a pressure relief and thus enables the maintenance of adhesion over prolonged periods. However, the absorption of sweat weakens the mechanical integrity of the adhesive and causes cohesively dominated failure during peel. These findings are also supported by the behavior of the adhesives on human skin before and after perspiration. This shows that the design of skin adhesives requires an intricate balance between viscoelasticity and sweat absorption in order to maintain adhesion during perspiration.

Section: Resultsmentioning

confidence: 74%

How the Viscoelastic and Sweat-Absorbing Properties of Skin Adhesives Affect Their Performance during Perspiration

Eiler

ACS Appl. Polym. Mater.

Bingöl

et al. 2020

Self Cite

Journal of Polymer Science

“…Adapted with permission. 16 Copyright 2020, American Chemical Society H-bonded to sulfonic acid groups, H-bonded to other water molecules, and non-H-bonded. They analyzed the depth profiles of the water species within the membrane during the fuel cell operation at various humidities and current densities.…”

Section: Water Diffusion In Polymersmentioning

confidence: 99%

“…To investigate water diffusion in polymer composites, Hansen et al used single-frequency CARS microscopy together with impedance spectroscopy as illustrated in Figure 12B. 16 CARS microscopy visualized real-time evolution of the polymer composite structure during water uptake while impedance spectroscopy evaluated water penetration. The polymer matrix (mixture of polyisobutylene and styrene-isoprene-styrene, PIB-SIS) was filled with either poly(acrylic acid) (PAA) or cetyl hydroxyethyl cellulose (CHEC) particles.…”

Section: Water Diffusion In Polymersmentioning

confidence: 99%

“…To investigate water diffusion in polymer composites, Hansen et al used single‐frequency CARS microscopy together with impedance spectroscopy as illustrated in Figure 12B 16 . CARS microscopy visualized real‐time evolution of the polymer composite structure during water uptake while impedance spectroscopy evaluated water penetration.…”

Section: Cars Imaging Of the Kinetics And Dynamics In Polymersmentioning

confidence: 99%

See 1 more Smart Citation

Coherent anti‐Stokes Raman scattering microscopy for polymers

Camp

Lee

2021

Coherent anti-stokes Raman scattering (CARS) microscopy is a label-free chemical imaging modality capable of interrogating local molecular composition, concentration, and even orientation. In comparison to traditional Raman spectroscopy/imaging, CARS generates signals that are typically orders-ofmagnitude stronger, enabling high-throughput and large-area imaging with superior spectroscopic fidelity. In this review, we present an overview of CARS microscopy as applied to polymer science, covering such timely and important topics as drug release and reaction kinetics to 3D molecular structures and orientation. We also discuss outstanding opportunities and challenges to using CARS microscopy as a quantitative measurement method.

“…In this study, we probe the propagation of the waterfront in skin adhesives through time-resolved impedance measurements and investigate the effect of the adhesive composition on the distribution of water. The impedance changes dramatically when the NaCl solution has penetrated through the adhesive and reached the working electrode . Knowing the adhesive thickness, the position of the waterfront is determined at the time of full penetration.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of Water Absorption in Polymer Skin Adhesives

Eiler

et al. 2020

ACS Appl. Bio Mater.

Self Cite

Skin adhesives are used to attach medical devices to the body and are required to adhere to the skin also during challenging conditions such as exposure to moisture and sweat. In order to maintain good skin–adhesive contact in these situations, the adhesives should be able to absorb water and remove fluids from the skin–adhesive interface. Consequently, the water absorption properties and distribution of water in the adhesives influence the overall adhesive properties. Understanding how the material composition impacts the absorption and distribution of water in these adhesives is required for rational formulation of skin adhesives. Here, we probe the dynamic water absorption in different skin adhesives using time-resolved impedance measurements and gravimetric analysis. Skin adhesive formulations consisting of soft, hydrophobic polymers providing stickiness, rigid block copolymers enhancing the structure, and hydrogel particles allowing for water uptake were designed. The hydrogel particle content and polymer matrix rigidity were varied, and the adhesives were systematically investigated to link the material composition and water absorption functionality.