Fluorescence recovery after photobleaching has been applied to determine, to our knowledge for the first time, the molecular weight () dependence of lateral diffusion of polymer chains within layer-by-layer (LbL) films. As shown by neutron reflectometry, polyelectrolyte multilayers containing polymethacrylic acid (PMAA, / < 1.05) of various molecular weights assembled from solutions of low ionic strengths at pH 4.5, where film growth was linear, showed similar diffusion of PMAA in the direction perpendicular to the film surface. At a salt concentration sufficient for unfreezing electrostatically bonded chains, layer intermixing remained almost unaffected (changes <1.0 nm), while the lateral diffusion coefficient () scaled with the PMAA molecular weight as .
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/mz400413v | DOI Listing |
Pharmaceutics
December 2024
Department of Pharmaceutical Sciences, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand.
Background/objectives: Crickets are recognized as an alternative source of chitosan. This study aimed to assess the potential of cricket-derived chitosan as a natural source to develop chitosan nanoparticles (CNPs).
Methods: Chitosan were isolated from different cricket species, including , , and .
Polymers (Basel)
December 2024
Department of Applied Mathematics, Materials Science and Engineering and Electronic Technology, Universidad Rey Juan Carlos, Calle Tulipán s/n, 28933 Móstoles, Spain.
This work investigates the sustainable reuse of expanded polystyrene (EPS) waste through a multi-cycle physical recycling process involving dissolution in acetone and subsequent manufacturing via Direct Ink Write (DIW) 3D printing and casting. Morphology and mechanical properties were evaluated as a function of the manufacturing technique and number of dissolution cycles. Morphological analysis revealed that casted specimens better replicated the target geometry, while voids in 3D-printed specimens aligned with the printing direction due to rapid solvent evaporation.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Catalysis Research Group (CRG), Department of Chemistry, College of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia.
This work focuses on the preparation and application of silver nanoparticles/organophilic clay/polyethylene glycol for the catalytic reduction of the contaminants methylene blue (MB) and 4-nitrophenol (4-NP) in a simple and binary system. Algerian clay was subjected to a series of treatments including acid treatment, ion exchange with the surfactant hexadecyltrimethylammonium bromide (HTABr), immobilization of polyethylene glycol polymer, and finally dispersion of AgNPs. The molecular weight of polyethylene glycol was varied (100, 200, and 4000) to study its effect on the stabilization of silver nanoparticles (AgNPs) and the catalytic activity of the resulting samples.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Department of Polymer and Biomaterials Science, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Al. Piastów 45, 70-311 Szczecin, Poland.
Photocurable materials offer a rapid transition from a liquid to a solid state, and have recently received great interest in the medical field. However, while dental resins are very popular, only a few materials have been developed for soft tissue repair. This study aims to synthesize a difunctional methacrylate monomer using a dibutyltin dilaurate which is suitable for the photocuring of soft materials.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
School of Energy and Building Environment, Guilin University of Aerospace Technology, Guilin 541004, China.
In this paper, we investigated the efficient metal-free phosphorus-nitrogen (PN) catalyst and used the PN catalyst to degrade waste PU with two-component binary mixed alcohols as the alcohol solvent. We examined the effects of reaction temperature, time, and other factors on the hydroxyl value and viscosity of the degradation products; focused on the changing rules of the hydroxyl value, viscosity, and molecular weight of polyols recovered from degradation products with different dosages of the metal-free PN catalyst; and determined the optimal experimental conditions of reaction temperature 180 °C, reaction time 3 h, and PN dosage 0.08%.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!