Arrangements of cationic starch of varying hydrophobicity on hydrophilic and hydrophobic surfaces

Kontturi, Katri S.; Holappa, Susanna; Johansson, Leena‐Sisko; Hyvärinen, Sari; Peltonen, Soili; Laine, Janne

doi:10.1016/j.jcis.2009.03.026

Cited by 13 publications

(7 citation statements)

References 48 publications

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“…This includes similar energy values for both hydrophobic surfaces (silica and TMSC) and also for both hydrophilic surfaces (silica and cellulose). Cellulose had a higher dispersive component than hydrophilic silica due to the amphiphilic nature of the cellulose molecule. , In agreement with earlier measurements, , we found a similar difference between dispersive components of hydrophilic and hydrophobic silica. The roughness variation of the surfaces was small, and all other surfaces except the partially desilylated TMSC surface can be considered to be smooth.…”

Section: Resultssupporting

confidence: 92%

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Bubble Attachment to Cellulose and Silica Surfaces of Varied Surface Energies: Wetting Transition and Implications in Foam Forming

et al. 2020

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To better understand the complex system of wet foams in the presence of cellulosic fibers, we investigate bubble−surface interactions by following the effects of surface hydrophobicity and surface tension on the contact angle of captive bubbles. Bubbles are brought into contact with model silica and cellulose surfaces immersed in solutions of a foaming surfactant (sodium dodecyl sulfate) of different concentrations. It is observed that bubble attachment is controlled by surface wetting, but a significant scatter in the behavior occurs near the transition from partial to complete wetting. For chemically homogeneous silica surfaces, this transition during bubble attachment is described by the balance between the energy changes of the immersed surface and the frictional surface tension of the moving three-phase contact line. The situation is more complex with chemically heterogeneous, hydrophobic trimethylsilyl cellulose (TMSC). TMSC regeneration, which yields hydrophilic cellulose, causes a dramatic drop in the bubble contact angle. Moreover, a high interfacial tension is required to overcome the friction caused by microscopic (hydrophilic) pinning sites of the three-phase contact line during bubble attachment. A simple theoretical framework is introduced to explain our experimental observations.

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Section: Resultssupporting

confidence: 92%

“…Surface modification of the Si-wafers was performed according to a modified procedure previously described in the literature. 51 First, the Si-wafers (10 × 10 mm) were cleaned with UVlight for 10 min. The Si-wafers were then hydrophilized by immersion in 2.5 M NaOH for 15 min.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Bubble Attachment to Cellulose and Silica Surfaces of Varied Surface Energies: Wetting Transition and Implications in Foam Forming

et al. 2020

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“…Model surfaces were prepared according to a modified procedure derived from the literature. 39 Si-wafer substrates (Okmetic, Espoo, Finland) were first cleaned with UV-Ozone (Procleaner, BioForce nanosciences, USA) for 10 min. Hydrophilization was achieved by immersing the surface in 2.5 M NaOH for 15 min, followed by thorough rinsing with Milli-Q water and drying with nitrogen gas.…”

Section: Fiber Materialsmentioning

confidence: 99%

Changing the Structural and Mechanical Anisotropy of Foam-Formed Cellulose Materials by Affecting Bubble–Fiber Interaction with Surfactant

Ketola

Song

Lappalainen

et al. 2022

ACS Appl. Polym. Mater.

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Cellulose fiber materials suitable for filtering, insulation, protective, and hygiene applications can be formed using aqueous foam as a carrier phase. The subtle fiber–bubble interaction provides a tool which can be utilized to alter both structural and mechanical material properties. Earlier model surface studies have only indicated clear surface-bubble adhesion when both the surface hydrophobicity and surface tension of the solution are high enough. In this work, we first show that for silica model surfaces these basic mechanisms are similar for both nonionic polyethylene glycol sorbitan monolaurate (Tween 20) and anionic sodium dodecyl sulfate (SDS) surfactants. In the second step, thick nonwoven materials were foam formed from hydrophilic or hydrophobic viscose fibers using small amounts of cellulose microfibers (CMFs) to form a bonding agent. There was a clear variation in structure and strength properties between the samples made using different fibers and surfactants. The partial alignment and layering of fibers in the wet foam led to anisotropy in the mechanical properties of the formed samples. Using SDS, the fiber alignment was very strong for hydrophilic fibers but was reduced for hydrophobic fibers because of stronger coupling to bubbles during structure forming, impacting the microscale fiber network. For nonionic Tween 20, in addition to surfactant adsorption on the fibers, the ethoxylated surfactant headgroups are suggested to form bridges between CMFs and other fibers, restricting fiber movements during formation. For hydrophilic fibers, this showed up as a lower in-plane compression modulus but higher transverse strength for Tween 20 compared with SDS surfactant. For hydrophobic fibers, the sensitivity of the mechanical properties on surfactant type was even stronger.

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“…Como pode ser observado na Tabela 47,48 . Esses estudos têm demonstrado que o uso de amidos quimicamente modificados ou a adição de outro polímero na matriz hidrofóbica pode aumentar o ângulo de contato, ou seja, a hidrofobicidade dos filmes produzidos 41 .…”

Section: Hidrofilicidadeunclassified

Produção E Caracterização Dos Filmes Biodegradáveis À Base De Amido De Mandioca: Influência Da Temperatura De Secagem

Lima¹,

Júnior²,

Nunes³

et al. 2021

Variantes Do Meio Ambiente: Atuação, Interdisciplinaridade E Sustentabilidade 2

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O objetivo desse estudo foi avaliar a influência do binômio tempo e temperatura de secagem (Ts) sobre as propriedades mecânicas e características físico-químicas dos filmes à base de amido de mandioca (FAM), obtidos pelo método casting, submetidos a estufa de secagem com convecção forçada. As melhores condições do binômio Ts e tempo foram 55°C/8,0h (FAM-55) e 60°C/5,5h (FAM-60) apresentando excelentes resultados para a resistência máxima à tração (2,92 ± 0,34 e 3,88 ± 0,77 MPa), respectivamente; sendo essas as condições escolhidas para a determinação dos demais parâmetros. FAM-55 e FAM-60 demonstraram ser uma barreira mais efetiva para a permeabilidade ao vapor d'água (PVA) com valores significativamente menores (3,81 ± 0,55 e 4,10 ± 0,54 g.mm.m -2 .dia -1 . kPa -1 ). As imagens geradas pelo MEV mostraram superfícies e áreas de seção transversal homogêneas para os FAM. Ausências de canais ou fissuras nos filmes e a uniformidade na espessura, confirmaram que as condições de produção: solução filmogênica gelatinizada a 70°C; sob agitação constante por 30 min; depositada em placa de acrílico (método casting), assim como as condições de secagem, favoreceram a produção de um material polimérico homogêneo proporcionando bons resultados de resistência à tração e melhores propriedades de barreira ao vapor d'água, quando comparado à literatura. Os FAM apresentaram elevada hidrofilicidade nos ensaios de ângulo de contato e rápida biodegradabilidade durante 12 dias. PALAVRAS-CHAVE: filmes à base de amido de mandioca, temperatura de secagem, propriedades mecânicas, permeabilidade ao vapor d'água, biodegradabilidade. INTRODUÇÃONos últimos anos, a crescente preocupação ambiental tem levado a indústria de alimentos a buscar alternativas às matrizes predominantemente baseadas em petróleo e não renováveis para aplicações em embalagens 1 . Filmes biodegradáveis têm sido investigados como

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Arrangements of cationic starch of varying hydrophobicity on hydrophilic and hydrophobic surfaces

Cited by 13 publications

References 48 publications

Bubble Attachment to Cellulose and Silica Surfaces of Varied Surface Energies: Wetting Transition and Implications in Foam Forming

Bubble Attachment to Cellulose and Silica Surfaces of Varied Surface Energies: Wetting Transition and Implications in Foam Forming

Changing the Structural and Mechanical Anisotropy of Foam-Formed Cellulose Materials by Affecting Bubble–Fiber Interaction with Surfactant

Produção E Caracterização Dos Filmes Biodegradáveis À Base De Amido De Mandioca: Influência Da Temperatura De Secagem

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