Water evaporation rates across hydrophobic acid monolayers at equilibrium spreading pressure

Tsuji, Mineo; Nakahara, Hiromichi; Moroi, Yoshikiyo; Shibata, Osamu

doi:10.1016/j.jcis.2007.10.047

Cited by 12 publications

(10 citation statements)

References 27 publications

(42 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The values found for E, and therefore E′, are significantly higher than those found in the literature for pure water or latex films drying in static air. 11,34,35 It should be noted, however, that the values reported here are obtained with an airflow in the climate chamber.…”

Section: ■ Results and Discussionmentioning

confidence: 92%

Film Formation of High T_g Latex Using Hydroplasticization: Explanations from NMR Relaxometry

et al. 2019

View full text Add to dashboard Cite

The film formation of acrylic latex dispersions, containing different amounts of carboxylic acid functional groups by the incorporation of methacrylic acid (MAA), was studied with GARField 1H NMR at various relative humidities (RH). Polymer particles with glass-transition temperatures in the range from 26 to 50 °C formed films at room temperature because of hydroplasticization. It was found that with an increased drying rate due to lower RH, the evaporation flux of water was limited by the latex polymer. Only in the second stage of drying this phenomenon was more obvious with increasing MAA content. 1H NMR relaxometry was used to study the change of hydrogen mobilities during film formation and hardening of the films. This showed that the drying rate itself had no impact on the hydrogen mobility in the latex films as measured via the T2 relaxation time. Hydrogen mobilities of water and the mobile polymer phase only significantly decrease after most water has evaporated. This implies that the rigidity of the polymers increases with the evaporation of water that otherwise plasticizes the polymer through hydrogen bonding with the carboxylic acid groups. This hardening of the polymer phase is essential for applications in a coating. The hydrogen mobilities were affected by the MAA concentration. Densities of mobile hydrogens increase with increasing MAA content. This is expected if the mobile protons are contained in the MAA groups. The result thus confirms the role of carboxylic acid groups in hydrogen bonding and plasticization of the copolymers. Hydrogen mobilities, however, decrease with increasing MAA content, which is hypothesized to be caused by the formation of dimers of carboxylic acid groups that still hold water. They still enable short-range polymer hydrogen mobility due to hydroplasticization but limit long-range polymer mobility due to interaction between the carboxylic acid groups.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 92%

Film Formation of High T_g Latex Using Hydroplasticization: Explanations from NMR Relaxometry

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Insoluble surfactants can be characterized by their equilibrium spreading pressure (ESP), which is the maximum equilibrium surface pressure that can be achieved by deposition of surfactant onto a water surface. Higher surface pressures can be achieved, for example, by compressing the surface material onto a smaller area, but these films would eventually relax to the ESP for the material. − ESPs are strongly temperature-dependent for the fatty acid and alcohol materials under study here, starting around 5–7 mN/m for C 18 acid , and ∼34 mN/m for octadecanol and decreasing with decreased temperature. − While measurements have not been made on supercooled water, ESPs less than 1 mN/m are expected at temperatures where freezing occurs for all surfactants used here. Because of this, the relevant phases are the L 1 , L 2 , L 2 ′, L 2 ″, and the 3D solid.…”

Section: Resultsmentioning

confidence: 97%

Relating Structure and Ice Nucleation of Mixed Surfactant Systems Relevant to Sea Spray Aerosol

et al. 2020

View full text Add to dashboard Cite

Ice nucleating particles (INPs) influence weather and climate by their effect on cloud phase state. Fatty alcohols present within aerosol particles confer a potentially important source of ice nucleation activity to sea spray aerosol produced in oceanic regions. However, their interactions with other aerosol components and the influence on freezing were previously largely unknown. Here, we report quantitative measurements of fatty alcohols in model sea spray aerosol and examine the relationships between the composition and structure of the surfactants and subphase in the context of these measurements. Deposited mixtures of surfactants retain the ability to nucleate ice, even in fatty acid-dominant compositions. Strong refreezing effects are also observed, where previously frozen water−surfactant samples nucleate more efficiently. Structural sources of refreezing behavior are identified as either kinetically trapped film states or three-dimensional (3D) solid surfactant particles. Salt effects are especially important for surfactant INPs, where high salt concentrations suppress freezing. A simple water uptake model suggests that surfactant-containing aerosol requires either very low salt content or kinetic trapping as solid particles to act as INPs in the atmosphere. These types of INPs could be identified through comparison of different INP instrument responses.

show abstract

“…26 This data can be used to determine the performance of a surface film, which is often reported as the ratio (φ) of the evaporation rate with a monolayer to the rate for water alone (φ = k m /k w ), with the effectiveness of the monolayer then defined as 1 -φ. 27 These results are shown in Table 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 12 As a comparison for evaluating the influence the externally applied force has on the surface film properties, the same experiment was carried out; however, in this case the centrifugal fan was not switched on, providing directly comparable results in a static environment. The water evaporation rates and effectiveness over 12 hours were calculated and are shown in Table 1 A significantly higher evaporation rate (8.5× higher) is observed in the dynamic system compared to the static system.…”

Section: Resultsmentioning

confidence: 99%

Dynamic Performance of Duolayers at the Air/Water Interface. 1. Experimental Analysis

et al. 2014

View full text Add to dashboard Cite

Understanding, and improving, the behavior of thin surface films under exposure to externally applied forces is important for applications such as mimicking biological membranes, water evaporation mitigation, and recovery of oil spills. This paper demonstrates that the incorporation of a water-soluble polymer into the surface film composition, i.e., formation of a three-duolayer system, shows improved performance under an applied dynamic stress, with an evaporation saving of 84% observed after 16 h, compared to 74% for the insoluble three-monolayer alone. Canal viscometry and spreading rate experiments, performed using the same conditions, demonstrated an increased surface viscosity and faster spreading rate for the three-duolayer system, likely contributing to the observed improvement in dynamic performance. Brewster angle microscopy and dye-tagged polymers were used to visualize the system and demonstrated that the duolayer and monolayer system both form a homogeneous film of uniform, single-molecule thickness, with the excess material compacting into small floating reservoirs on the surface. It was also observed that both components have to be applied to the water surface together in order to achieve improved performance under dynamic conditions. These findings have important implications for the use of surface films in various applications where resistance to external disturbance is required.

show abstract

Water evaporation rates across hydrophobic acid monolayers at equilibrium spreading pressure

Cited by 12 publications

References 27 publications

Film Formation of High T_g Latex Using Hydroplasticization: Explanations from NMR Relaxometry

Film Formation of High T_g Latex Using Hydroplasticization: Explanations from NMR Relaxometry

Relating Structure and Ice Nucleation of Mixed Surfactant Systems Relevant to Sea Spray Aerosol

Dynamic Performance of Duolayers at the Air/Water Interface. 1. Experimental Analysis

Contact Info

Product

Resources

About

Water evaporation rates across hydrophobic acid monolayers at equilibrium spreading pressure

Cited by 12 publications

References 27 publications

Film Formation of High Tg Latex Using Hydroplasticization: Explanations from NMR Relaxometry

Film Formation of High Tg Latex Using Hydroplasticization: Explanations from NMR Relaxometry

Relating Structure and Ice Nucleation of Mixed Surfactant Systems Relevant to Sea Spray Aerosol

Dynamic Performance of Duolayers at the Air/Water Interface. 1. Experimental Analysis

Contact Info

Product

Resources

About

Film Formation of High T_g Latex Using Hydroplasticization: Explanations from NMR Relaxometry

Film Formation of High T_g Latex Using Hydroplasticization: Explanations from NMR Relaxometry