Interfacial Stabilization of Multiphase Systems with (Ligno)cellulosic (Nano)materials and Surfactants

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School of Chemical Technology | Doctoral thesis (article-based) | Defence date: 2019-12-05
Degree programme
58 + app. 92
Aalto University publication series DOCTORAL DISSERTATIONS, 216/2019
This thesis explores the interactions between (ligno)cellulosic (nano)materials and surfactants and evaluates their impact on interfacial activities relevant to multiphase systems, namely, foams and emulsions. The main plant-based components consider supramolecular constructs of cellulose, wood fibers, nanofibrils, cellulose carrying residual cell-wall molecules as well as non-cellulosics that are leached from fibers. The presented discussion focuses on phenomena relevant to the gas/liquid and liquid/liquid interfaces, the synergism between an anionic surfactant (sodium dodecyl sulfate, SDS) and like-charged (nano)cellulosic materials (wood fibers and cellulose nanofibrils, CNF). SDS is found to induce the leaching of non-cellulosics from wood fibers or CNF, which form surface-active aggregates with SDS. They effectively lower the gas/liquid interfacial tension and enhance foamability and foam stability, mainly by reducing drainage, coalescence, and coarsening. As an extension of the work with foams, they were used to produce wood fiber networks (foam-laying) from a wide selection of fibers and surfactant types. The cause-effect relations, the structuring mechanisms and the physico-mechanical properties of the fiber networks are revealed. The major drawback of typical foam-laid materials, namely, the loss of in-plane and out-of-plane strength, is addressed by replacing synthetic surfactants with an alternative surface active substance, carboxymethylated lignin. As an extension to foams and based on the uncovered interactions between cellulose and surfactants, the study turned to cellulose nanocrystals (CNC), which were considered in the formulation of food-grade emulsions. The synergism between an oppositely-charged surfactant (food-grade ethyl lauroyl arginate, LAE) and CNC is found to provide Pickering emulsions with outstanding stability. Taken together, the incorporation of plant-based components in the formulation of foams and emulsions is presented as an option in the framework of the future bioeconomy. The findings presented contribute to the effective and efficient utilization of natural resources for growing areas pertaining to multiphase systems.
Supervising professor
Rojas, Orlando, Prof., Aalto University, Department of Bioproducts and Biosystems, Finland
Thesis advisor
Bai, Long, Dr., Aalto University, Department of Bioproducts and Biosystems, Finland
Tardy, Blaise L., Dr., Aalto University, Department of Bioproducts and Biosystems, Finland
Rojas, Orlando, Prof., Aalto University, Department of Bioproducts and Biosystems, Finland
lignocellulose, surfactant, synergism, aqueous foams, foam-laying, pickering emulsions
Other note
  • [Publication 1]: Xiang, Wenchao; Preisig, Natalie; Laine, Christiane; Hjelt, Tuomo; Tardy, L. Blaise; Stubenrauch, Cosima; Rojas, J. Orlando. Surface Activity and Foaming Capacity of Aggregates Formed between an Anionic Surfactant and Non-Cellulosics Leached from Wood Fibers. Biomacromolecules, 2019, 20 (6), 2286-2294.
  • [Publication 2]: Xiang, Wenchao; Preisig, Natalie; Ketola, Annika; Tardy, L. Blaise; Bai, Long; Ketoja, A. Jukka; Stubenrauch, Cosima; Rojas, J. Orlando. How Cellulose Nanofibrils Affect Bulk, Surface, and Foam Properties of Anionic Surfactant Solutions. Accepted by the journal Biomacromolecules in the year of 2019.
    DOI: 10.1021/acs.biomac.9b01037 View at publisher
  • [Publication 3]: Xiang, Wenchao; Filpponen, Ilari; Saharinen, Erkki; Lappalainen, Timo; Salminen, Kristian; Rojas, J. Orlando. Foam Processing of Fibers as a Sustainable Alternative to Wet-Laying: Fiber Web Propertiesand Cause-Effect Relations. ACS Sustainable Chemistry & Engineering, 2018, 6 (11), 14423-14431.
    Full text in Acris/Aaltodoc:
    DOI: 10.1021/acssuschemeng.8b03102 View at publisher
  • [Publication 4]: Li, Shuai; Xiang, Wenchao; Järvinen, Marjo; Lappalainen, Timo; Salminen, Kristian; Rojas, J. Orlando. Interfacial Stabilization of Fiber-Laden Foams with Carboxymethylated Lignin toward Strong Nonwoven Networks. ACS Applied Materials & Interfaces, 2016, 8 (30), 19827-19835.
    DOI: 10.1021/acsami.6b06418 View at publisher
  • [Publication 5]: Bai, Long; Xiang, Wenchao; Huan, Siqi; Rojas, J. Orlando. Formulation and Stabilization of Concentrated Edible Oil-in-Water Emulsions Based on Electrostatic Complexes of a Food-Grade Cationic Surfactant (Ethyl Lauroyl Arginate) and Cellulose Nanocrystals. Biomacromolecules, 2018, 19 (5), 1674-1685.
    Full text in Acris/Aaltodoc:
    DOI: 10.1021/acs.biomac.8b00233 View at publisher