The effect of the surface charge of nucleation agents on the crystallization behavior of poly(vinylidene fluoride) (PVDF) has been investigated. Ion-dipole interaction between the positive surface of nucleation agents and the partially negative CF(2) dipoles of PVDF is established as a main factor for further lowering the free energy barrier for nucleation, and thus increasing significantly the crystallization kinetics. This is in contrast to the behavior observed for nucleation agents possessing either negative surface or neutral charges. Positive nucleation agents led to a remarkable increase in the crystallization temperature of PVDF (lower supercooling) as compared with that of neat PVDF. The dispersion of each type of nucleation agent is also important. The melting temperatures of nucleation agents need to be higher than the melting temperature of PVDF. The melting point and degree of crystallinity of PVDF can also be raised by using specific nucleation agents. The detailed crystallization kinetics and conformational changes of the PVDF chain have been investigated. With the addition of positive nucleation agents, the γ and β chain conformations, instead of the α phase, dominate.
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Alzheimers Dement
December 2024
ADEL Institute of Science & Technology (AIST), ADEL, Inc., Seoul, Korea, Republic of (South).
Background: Beta-2 microglobulin (β2m) is a component of the major histocompatibility complex class I (MHC-I) playing a crucial role in the immune system on cell surface, but it can be separated from the MHC-I and exist in biological fluid independently. Numerous reports have shown that β2m is a systemic pro-aging factor impairing cognitive function, and that it is increased in the blood and CSF of patients with Alzheimer's disease (AD). While β2m in the body fluid has been recognized as a potential factor in AD and aging, the development of therapeutic agents, especially those directly targeting β2m using antibodies, may face challenges.
View Article and Find Full Text PDFSci Rep
December 2024
Institute of Radioelectronics and Multimedia Technology, Warsaw University of Technology, Warsaw, Poland.
The effects of 5.8-GHz microwave (MW) irradiation on the synthesis of mesoporous selenium nanoparticles (mSeNPs) in aqueous medium by reduction of selenite ions with ascorbic acid, using zinc nanoparticles as a hard template and cetyltrimethylammonium bromide (CTAB) as a micellar template, are examined for the first time with a particular emphasis on MW-particle interactions and the NPs morphology. This MW-assisted synthesis is compared to 2.
View Article and Find Full Text PDFJ Phys Chem B
December 2024
State Key Laboratory of Physical Chemistry of Solid Surface, Key Laboratory of Chemical Biology of Fujian Province, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China.
Nucleation is a critical step that determines the assembly pathway and the structure and functions of the peptide assemblies. However, the dynamic evolution of interactions between nucleating agents and peptides, as well as between peptides themselves during the nucleation process, remains elusive. Herein, we show that the heterogeneous nucleating agent carboxymethylcellulose (CMC) can promote the nucleation of Aβ (KF) peptide.
View Article and Find Full Text PDFJ Photochem Photobiol B
December 2024
Department of Applied Science and Technology, A C Tech, Anna University, Chennai-600025, Tamil Nadu, India.
A novel method for synthesizing nanomaterials involves microbial or phytochemical nano-factories, which offer an eco-friendly, cost-effective, and reliable approach to producing clean and reproducible products. In this study, magnesium oxide nanoparticles (MgO NPs) were synthesized using Avicennia marina, a marine plant, as both a nucleation and stabilizing agent. The MgO NPs were characterized for crystallinity, cut-off wavelength, morphology, thermal stability, and surface properties using XRD, EDX, BET, UV-Visible spectroscopy, DLS, zeta potential analysis, SEM, TEM, TGA/DTA, and PL spectroscopy.
View Article and Find Full Text PDFSmall
December 2024
School of Materials and Energy, Yunnan University, Kunming, 650091, China.
Perovskite solar cells (PSCs) have achieved impressive efficiency, but their commercialization is limited by issues like chemical homogeneity within the perovskite films, leading to defects and phase segregation, which severely compromise the stability and performance of PSCs. This study presents a novel approach to overcoming these barriers by employing N,N-methylenebisacrylamide (MBA) as a multifunctional crosslinking agent within the perovskite structure. MBA enhances chemical uniformity both laterally and vertically, improves crystallinity, and boosts overall film stability by forming a robust crosslinked network that regulates nucleation and growth dynamics during the pre-seeding process.
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