Preparations and properties of thermosensitive terpolymers of N‐isopropylacrylamide, sodium 2‐acrylamido‐2‐methyl‐propanesuphonate, and N‐tert‐butylacrylamide

Abstract

Terpolymers based on N-isopropylacrylamide, sodium 2-acrylamido-2-methyl-propanesulfonate, and N-tertbutylacrylamide were synthesized by free-radical copolymerization with 2,2 0 -azobisisobutyronitrile as an initiator. The lower critical solution temperatures (LCSTs) of the linear polymer aqueous solutions were determined by the measurement of the transmittance on UV at different temperatures. The influence of the polymer concentration, polymer composition, and ionic strength on the LCSTs of the linear polymers was investigated. The LCST decreased with increases in the hydrophobic monomer N-tert-butylacrylamide, polymer concentration, and ionic strength. The phase transition became sharp when the polymer concentration and ionic strength increased. Meanwhile, the crosslinked hydrogels were prepared with the same recipe used for the linear terpolymers, but a crosslinker was added to the reaction system. The swelling ratios of the hydrogels at various temperatures and salt solutions were determined. The hydrogels possessed both high swelling ratios and thermosensitivity.

Hyaluronic Acid-Conjugated Thermoresponsive Polymer-Based Bioformulation Enhanced Wound Healing and Gut Barrier Repair of a TNBS-Induced Colitis Injury Ex Vivo Model in a Dynamic Perfusion Device

“…Following the latter concept, NTBAM monomers were used along with NIPAM monomers (during the initial step 1 polymerization reaction) for the preparation of the graft copolymer to ensure the thermoresponsive nature of the final grafted P­(NIPAM- co -NTBAM)-HA below 37 °C (Figure A,B). This was in line with previous studies, which report that NTBAM monomers have an additional hydrophobic group and thus results in reduction of the polymer–water interactions, leading to the decrease in LCST . Three different feed ratios of P­(NIPAM- co -NTBAM)-NH 2 (with 58.31% NH 2 functionalization) and HA were used to determine the polymer constitution of the formulation for obtaining optimal properties.…”

“…This was in line with previous studies, which report that NTBAM monomers have an additional hydrophobic group and thus results in reduction of the polymer−water interactions, leading to the decrease in LCST. 46 Three different feed ratios of P(NIPAM-co-NTBAM)-NH 2 (with 58.31% NH 2 functionalization) and HA were used to determine the polymer constitution of the formulation for obtaining optimal properties. Based on percentage conjugation efficiency and LCST of the formulation around 35 °C (Supporting Information, Table S2), the final 5% w/v polymeric reaction was set by using P(NIPAM-co-NTBAM)-NH 2 (prepared from step 1) and HA in a 70:30 ratio.…”

Simultaneous Enhancement of Cell Proliferation and Thermally Induced Harvest Efficiency Based on Temperature-Responsive Cationic Copolymer-Grafted Microcarriers

“…28 However, the LCST of PIPAAm-based copolymers containing ionic monomer units is known to be reduced by the copolymerization of an adequate amount of hydrophobic monomer. 30,31 Indeed, the copolymerization of both APTAC and hydrophobic tBAAm in the copolymer brush resulted in an increase in the contact angle of the PIAT beads compared to that of the PIA beads at 37 °C. As a result, the contact angle of the PIAT beads exhibited a significant change in contact angle with a decrease in temperature from 37 to 25 °C.…”

Unusual effect of molecular weight and concentration on thermoresponsive behaviors of well‐defined water‐soluble semirigid polymers

“…Stimuli‐responsive materials, also known as smart materials, undergo conformational transitions induced by environmental changes, such as temperature,1–3 salts,4–6 pH,2, 7, 8 or light 9–12. Thermoresponsive polymers with lower critical solution temperature (LCST) have gained increasing attention for their potential application in controlled drug delivery systems,13–15 tissue engineering,16, 17 biotechnology,18, 19 nanotechnology,20, 21 sensors and separation processes,22, 23 and so on.…”