Article
Polymer Science
Chi Wang, Takeji Hashimoto, Ya-Chen Chuang, Keiji Tanaka, Yen-Pin Chang, Ting-Wei Yang, Meng-Tse Huang
Summary: This study investigates the phase transitions and gelation properties of aqueous solutions of atactic poly(N-isopropylacrylamide). The gel point and critical gel temperature were determined, and a phase diagram was constructed to describe the different phases of the solution. The structure and formation mechanism of gel junctions were also explored.
Article
Biochemistry & Molecular Biology
Lais Ramos Monteiro Lima, Everton Lucas de Lima Ramos, Maria Francilene Souza Silva, Fabio de Oliveira Silva Ribeiro, Jeanlex S. Sousa, Claudia Pessoa, Durcilene Alves Silva, Judith P. A. Feitosa, Haroldo C. B. Paula, Regina Celia Monteiro de Paula
Summary: In this study, aminated poly(N-isopropylacrylamide) was successfully grafted onto oxidized galactomannan polysaccharide from Delonix regia via Schiff base reaction. The self-organizing ability of the obtained nanoparticle copolymers was investigated, showing promising potential for drug delivery with good cell viability and transition temperature close to human body temperature. The use of free aldehyde groups in the oxidized polysaccharide for pro-drug formation with substances possessing NH2 groups was also highlighted.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2021)
Article
Polymer Science
Chuhao Qiu, Weixiang Sun, Tao Wang, Zhen Tong
Summary: When a copolymer network of chemically crosslinked poly(n-butyl methacrylate-co-methacrylic acid) is immersed into a bath of N,N-dimethylformamide (DMF) and water, the network undergoes phase separation depending on the water fraction in the bath. The properties of the swollen network, such as swelling ratio, light transmittance, thermomechanics, dynamical mechanical spectra, and tensile property, were investigated for different water fractions. The results showed that the polymer-rich phase after phase separation became glassy when the water fraction in the bath was above 0.75. This led to a fundamental change in the thermomechanical behavior of the gel. A dynamical gel-to-glass transition was also observed, and its transition temperature decreased with increasing water fraction.
Article
Polymer Science
Atieh Razavi, Matthias Rutsch, Sonja Wismath, Mario Kupnik, Regine von Klitzing, Amin Rahimzadeh
Summary: This study investigates the use of high-frequency ultrasound to stimulate PNIPAM microgels and break the hydrogen bonds between water molecules. The absorption of ultrasound energy leads to the collapse of microgels and an increase in solution turbidity. The increase in solution concentration and ultrasound frequency accelerates the evolution of turbidity.
Article
Chemistry, Multidisciplinary
Elizabeth Howard, Minghao Li, Michael Kozma, Jiayu Zhao, Jinhye Bae
Summary: This study reports the continuous self-strengthening of a nanocomposite hydrogel composed of poly(N-isopropylacrylamide) and nanoclay using external stimuli such as heat and ionic strength. The internal structures of the hydrogel are rearranged through swelling-deswelling cycles or immersion in a salt solution, leading to significant improvements in its mechanical properties. The loading ability demonstrates the self-strengthening mechanical performance of the hydrogel.
Article
Chemistry, Multidisciplinary
Mitsuhiro Matsumoto, Taka-Aki Asoh, Tatsuya Shoji, Yasuyuki Tsuboi
Summary: This study demonstrates liquid-liquid phase separation of a thermoresponsive polymer through near-infrared laser-induced coacervation and coil-to-globule phase transition. By focusing a laser beam, single polymer microdroplets can be formed and trapped at the focal point, allowing for selective analysis. The results indicate that PDEA undergoes dehydration and coacervation in addition to a coil-to-globule phase transition.
Article
Chemistry, Applied
Birgul Kalkan, Nermin Orakdogen
Summary: This study synthesized thermoresponsive semi-interpenetrating polymer networks (semi-IPNs) by varying the content of linear polyacrylamide (PAAm), N-isopropylacrylamide (NIPA), and methacrylic acid (MA). The inclusion of linear PAAm chains increased the crosslinking density and compressive elasticity of the P(NIPA-MA) network. The swelling behavior of the semi-IPN gels was sensitive to the presence of linear PAAm chains, and their equilibrium swelling was decreased compared to the copolymer P(NIPA-MA) network. The prepared semi-IPNs exhibited good adsorption properties for the cationic dye Methyl violet (MV).
REACTIVE & FUNCTIONAL POLYMERS
(2022)
Article
Nanoscience & Nanotechnology
Xuejiao Wang, Dongzhi Yang, Ming Zhang, Qian Hu, Kejing Gao, Jingsheng Zhou, Zhong-Zhen Yu
Summary: Super-hygroscopic gels composed of calcium chloride/graphene oxide/poly(N-isopropylacrylamide) are designed for spontaneous collection of atmospheric water and solar-driven release of the absorbed water.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Polymer Science
Chia-Hsin Ko, Cristiane Henschel, Geethu P. Meledam, Martin A. Schroer, Renjun Guo, Luka Gaetani, Peter Mueller-Buschbaum, Andre Laschewsky, Christine M. Papadakis
Summary: The self-assembly of the thermoresponsive amphiphilic diblock copolymer PMMA(21)-b-PNIPAM(283) in various water/methanol mixtures was studied. It was found that the solvent composition significantly affected the internal morphology of micelles and the conformation of dissolved chains.
Article
Acoustics
Masaki Kubo, Masato Higuchi, Tomoyuki Koshimura, Eita Shoji, Takao Tsukada
Summary: A novel method was developed in this study to control the responsive temperature of poly(NIPAM-co-HEMA) using ultrasonic polymerization technique. Ultrasonic irradiation affected the initiation reaction and polymer degradation, but did not affect the propagation reaction. The lower critical solution temperature (LCST) of the copolymer was found to increase with increasing ultrasonic irradiation time.
ULTRASONICS SONOCHEMISTRY
(2021)
Article
Polymer Science
Chia-Hsin Ko, Cristiane Henschel, Geethu P. Meledam, Martin A. Schroer, Peter Mueller-Buschbaum, Andre Laschewsky, Christine M. Papadakis
Summary: The temperature-dependent phase behavior and self-assembly behavior of a thermoresponsive amphiphilic diblock copolymer in aqueous solution were studied, revealing a lower critical solution temperature (LCST) behavior at 31.1 degrees Celsius and the formation of different structures of micelles.
Article
Polymer Science
Migle Babelyte, Laura Peciulyte, Vesta Navikaite-Snipaitiene, Joana Bendoraitiene, Volodymyr Samaryk, Ramune Rutkaite
Summary: Thermoresponsive chitosan-graft-poly(N-isopropylacrylamide) copolymers with different compositions were synthesized. The chemical structure of the copolymers was confirmed and their lower critical solution temperature (LCST) behavior was assessed. Copolymers with a certain content of poly(N-isopropylacrylamide) side chains demonstrated LCST behavior and could potentially be used in drug delivery systems or tissue engineering.
Article
Polymer Science
Qichen Tang, Shanhua Qian, Weiwei Chen, Xiaofei Song, Jianfeng Huang
Summary: In this study, Ca-alginate/PNIPAm hydrogels were prepared through physical crosslinking and chemical crosslinking, and their properties were characterized. The results showed that the pure PNIPAm hydrogel obtained using thermal initiation polymerization exhibited better swelling and temperature-responsive properties compared to the hydrogel using ultraviolet polymerization. The mechanical properties of the Ca/PNIPAm hydrogel were enhanced when the SA concentration exceeded 8 wt%.
POLYMER INTERNATIONAL
(2023)
Article
Polymer Science
Yiluo Hu, Younghyun Shin, Sohyun Park, Jae-pil Jeong, Yohan Kim, Seunho Jung
Summary: Self-healing and temperature/pH-responsive hydrogels were prepared by using oxidized succinoglycan (OSG) and a poly (N-isopropyl acrylamide-co-acrylamide) [P(NIPAM-AM)] copolymer. OSG, synthesized from succinoglycan (SG) isolated directly from soil microorganisms, showed improved elasticity, thermal stability, self-healing ability, and tensile strength compared to P(NIPAM-AM) hydrogels. The OSG/P(NIPAM-AM) hydrogels also exhibited effective temperature/pH-responsive drug release and non-toxicity, suggesting their potential for biomedical applications such as drug delivery systems, wound healing, scaffolds, and tissue engineering.
Article
Polymer Science
Yiluo Hu, Yohan Kim, Jae-pil Jeong, Sohyun Park, Younghyun Shin, In Ki Hong, Moo Sung Kim, Seunho Jung
Summary: In this study, temperature/pH-responsive hydrogels based on succinoglycan (SG) and poly(N-isopropylacrylamide) (PNIPAM) were prepared. The hydrogels exhibited improved thermal stability and mechanical properties, and showed potential as a temperature/pH-dependent drug release system.
EUROPEAN POLYMER JOURNAL
(2022)