Effect of sodium hydroxide solution as polymerization solvent and activator on structural, mechanical and antibacterial properties of PNIPAAm and P(NIPAAm–clay) hydrogels

Abstract

Poly(N‐isopropylacrylamide) (PNIPAAm) and its composite hydrogels were synthesized by free‐radical polymerizations in NaOH solutions (0.1, 0.2 N). Laponite (LP), Montmorillonite (MMT) and ODA(octadecylamine)‐MMT were used as inorganic multicrosslinkers while BIS was chosen as conventional crosslinker. All polymerizations were initiated with KPS alone. The effects of two different concentrations of NaOH‐KPS redox pair and long reaction times (1w and 2w) at 25°C on structural and mechanical properties, antibacterial and haemolytic activities of the modified hydrogels were studied by conductometric titrations, FTIR, XRD, EDX, compression, inhibition zone and haemolysis tests. Their homogenities, compressive moduli at 37°C, antibacterial activities and blood compatibilities increased with increasing reaction time and NaOH concentration. POLYM. COMPOS., 39:E386–E406, 2018. © 2017 Society of Plastics Engineers

Tuning Compressive Young’s Moduli and Antibacterial Activities of Alginate/Poly(N-isopropylacrylamide) Hydrogels with Laponite Layers and Cerium Ions

“…Scheme describes the PNIPAAm-based hydrogel formations via free radical solution polymerization with BIS molecules (a) or laponite layers (b) as crosslinkers, followed by external gelation with cerium ions. PNIPAAm and Alg/PNIPAAm hydrogels crosslinked with LP RD (L0/L2/L4/L6) can be considered comb-type hydrogels that the laponite layers loaded with negative charges behave like backbones decorated with many PNIPAAm brushes. , The brushes initiated with the KPS/TEMED redox pair are connected onto the charged layers by ionic interactions. Some of the growing PNIPAAm brushes form bridges between different laponite layers, called multicrosslinkers.…”

“…Haraguchi reported that the mechanical properties, swelling/deswelling processes, and homogeneity of PNIPAAm hydrogels were markedly improved by clay layers acting as inorganic multicrosslinkers through ionic and/or polar interactions, compared to chemical crosslinking by divinyl crosslinkers. , Ye et al reported the preparation of pH- and temperature-sensitive hybrid PNIPAAm hydrogels composed of polyanionic Alg and laponite-XLG (synthetic hectorite) as a natural pH-sensitive component and multicrosslinker, respectively . In our previous studies, the effects of various initiator–activator pairs on the mechanical properties of both PNIPAAm-montmorillonite (MMT) and PNIPAAm-laponite RD hydrogels have been demonstrated. − …”

“… 18 In our previous studies, the effects of various initiator–activator pairs on the mechanical properties of both PNIPAAm-montmorillonite (MMT) and PNIPAAm-laponite RD hydrogels have been demonstrated. 19 − 21 …”

Effect of Mg doping on morphology, photocatalytic activity and related biological properties of Zn1−xMgxO nanoparticles

“…Human whole blood samples were used in the experiments and hemolytic activity of NPs were investigated according to earlier reports [67]. 4 mL of human blood anticoagulated with trisodium citrate solution (0.108 mM) was added to 10 mL of Ca and Mg free PBS solution and centrifuged at 2000 rpm for 5 min to separate the erythrocytes from plasma.…”

Effect of divalent ion of strontium substitution on the structural, optical, magnetic and blood compatibility studies in cobalt ferrite

“…UV spectra for the supernatant of each sample were recorded to quantify the degree of hemolysis indicating cell lysis. The degree of hemolysis for each nanoparticle sample was calculated using the absorbance (ABS) value of the supernatant at 540 nm according to the expression given below [53].…”