For the first time, by using precipitation polymerization in an aqueous solution, a cross-linked poly(acrylic acid)-(pAA) nanogel was synthesized. pAA was synthesized and cross-linked with ,'-methylenebisacrylamide (BIS) at 70°C in an acidified environment (pH 2) and containing 0.7 M NaCl using potassium persulfate as the initiator. Ionized pAA was soluble in water. The use of sodium chloride at low pH caused a decrease in the solubility of pAA and led to its precipitation and formation of cross-linked pAA nanogel. By using electron microscopies and light scattering techniques, the morphology, pH sensitivity and zeta potential of the obtained p(AA-BIS) nanogel were evaluated. The polymerization in an aqueous environment resulted in a very big swelling/shrinking coefficient (of approx. 4000) in response to pH and exhibited an unusually high negative zeta potential (of approx. -130 mV). These properties make the nanogel a very interesting sorbent and a construction material.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6894567 | PMC |
http://dx.doi.org/10.1098/rsos.190981 | DOI Listing |
Int J Mol Sci
November 2024
Department of Chemistry, Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 162-8601, Japan.
Covalent adaptable networks (CANs) are polymer networks cross-linked via dynamic covalent bonds that can proceed with bond exchange reactions upon applying external stimuli. In this report, a series of cross-linked polyacrylate films were fabricated by changing the combination of acrylate monomer and the amount of diacrylate cross-linker possessing oxime-urethane bonds as a kind of dynamic covalent bond to evaluate their rheological relaxation properties. Model analysis of the experimental relaxation curves of cross-linked polyacrylate films was conducted by assuming that they consist of two types of relaxation, one of which is related to the oxime-urethane bond exchange reaction, and another of which is associated with the melting of the aggregated cross-linker.
View Article and Find Full Text PDFToxicology
January 2025
Department of Occupational Pneumology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahata-nishi-ku, Kitakyushu, Fukuoka 807-8555, Japan. Electronic address:
ACS Appl Eng Mater
October 2024
Laboratory of Biomechanical Orthopedics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland.
Dissipative materials are essential for mitigating impact in various automotive, aerospace, and sports equipment applications. This study investigates the efficiency of a novel hybrid iono-organogel in dissipating and absorbing impact energies. The gel consists of a covalently cross-linked poly(acrylic acid)--poly(zwitterionic (DMAPS)) in a hybrid solvent system composed of the ionic liquid [COHMIM][BF] and the oligomer PEG200.
View Article and Find Full Text PDFAdv Mater
November 2024
School of Mechanical Engineering, Korea University, Seoul, 02841, Republic of Korea.
ACS Appl Mater Interfaces
October 2024
Department of Polymer Materials and Engineering, School of Materials Science and Engineering, Chang'an University, Xi'an 710064, China.
Natural tissues, like ligaments and tendons, display not just robust mechanical performance but also complex anisotropic structures extending beyond one-directional arrangements. However, fabricating hydrogel actuators with biomimetic three-dimensional anisotropy remains challenging. Herein, a simple strategy involving curving-stretching induced alignment is proposed to prepare anisotropic Fe-cross-linked poly(acrylic acid)-poly(acrylamide) hydrogel actuators.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!