Preparation And Properties Of Surfactant-polyvinyl Alcohol Composite Hydrogel

In recent years,increased emphasis from consumers on product sustainability and upgrading has caused several shifts in development focus by the consumer goods chemical industry.Consequentially,the development of new surfactants and surfactant-delivery platforms that are able to balance performance,biodegrability and portability have become pillars in the product development strategy of these businesses.Recent efforts focused on the development of laundry gel pods wrapped with polyvinyl alcohol as an outer film have achieved great success in industrialization and marketization.However,in order to ensure the stability of the polyvinyl alcohol film,the surfactant of laundry gel pods was limited to non-ionic surfactants formula with very low water content,thus limiting the application of those delivery platforms to personal care.One viable option to mitigate these shortcomings is to design new cleaning products based on hybrid polymer-surfactant composites,thus enabling them to be stably compounded with a variety of surfactants.Furthermore,these formulations have the added benefit of offering dense,lightweight dosing units,providing the added benefit of product portability.This,along with the platform geometrical malleability,has provided a substantial amount of attention on the use of polyvinyl alcohol-surfactant complexes as delivery platforms for cleaning agents.However,there are some drawbacks on this technology,including: limited types of compatible surfactants,and the lack of robust solubility and mechanical properties.This study aims to understand the main factors affecting the physical properties of surfactant-polyvinyl alcohol composite hydrogels,in order to provide a roadmap for surfactant selection in future formulas.In this study,polyvinyl alcohol is used as the structural matrix with glycerin as the cross-linking agent.Different combinations of nonionic,zwitterionic and amino acid surfactants were used to prepare various surfactant-polyvinyl alcohol solutions.Rheological properties of these were investigated using a cone plate setup at a fixed rate.These results help predict the relationship between polyvinyl alcohol and surfactant in aqueous solution.Subsequently,an aluminium alloy plate was employed as drying tray to form hydrogel strips targeting moisture contents of approximately15%.The mechanical properties of the dried hydrogel were analysed using a material testing system(MTS).Tensile strength testing results indicate hydrogels with more linear and uniformly charged surfactant possess more resilient tensile properties better performance.Additionally,X-ray diffraction(XRD)was employed to analyze the crystalline phase structure of the sample.Furthermore,the lattice morphology was found to be adjustable based on the surfactant compositions,thus giving formulators a control knob for the optimization of hydrogel mechanical properties.It was found that the crystallinity affects the mechanical properties of the surfactant-polyvinyl alcohol hydrogel.As the pure crystallinity of the composite hydrogel increases,its peak fracture load gradually increases;as the crystallinity of the composite hydrogel liquid crystal increases,its elongation at break also increases.Scanning electron microscope(SEM)imagery was captured to further the understanding of the hydrogel microstructure.By comprehensively examining rheological and dissolution properties,as well as the SEM characteristics,we propose the following surfactant-PVA absorption model.These findings will allow formulators to leverage the intrinsic characteristics of surfactants and explore possible mechanisms of adsorption with polyvinyl alcohol.