Effect of pH on the Dynamics and Structure of Thermoresponsive Telechelic Polyelectrolyte Networks: Impact on Hydrogel Injectability
Effect of pH on the Dynamics and Structure of Thermoresponsive Telechelic Polyelectrolyte Networks: Impact on Hydrogel Injectability
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DOI：
10.1021/acsapm.0c01159
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发表时间：
2021-01-20
影响因子：
5
通讯作者：
Tsitsilianis, Constantinos
中科院分区：
文献类型：
--
作者：
Lencina, Maria Malvina Soledad;Ko, Chia-Hsin;Tsitsilianis, Constantinos
我们报告了 pH 对 P(nBuMA(18)-co-TEGMA(15))-b-PDMAEMA(159)-b-P(nBuMA(18)-co-TEGMA(15)) 末端嵌段的温度依赖性疏水缔合形成的 3D 网络的动力学和结构的影响，其中 PDMAEMA 和 P(TEGMA-co-nBuMA) 代表聚（N,N-二甲基氨基乙基甲基丙烯酸酯）和水性介质中的聚（分别为三乙二醇甲醚甲基丙烯酸酯/甲基丙烯酸正丁酯）三嵌段三元共聚物。由于可以通过温度独立控制的粘性末端嵌段的设计，可以通过振荡流变学和小角度中子散射来探索pH效应，影响亲水性中间嵌段的电荷密度和链构象，对网络动力学和结构的影响。观察到三种 pH 状态：在低 pH（6）下，观察到 tau 显着增加（约 6 倍），这可能是由于电荷密度的降低和促进交联的聚（2-二甲基氨基乙基甲基丙烯酸酯）（PDMAEMA）块的链柔性增加而导致网络连接性的增强，如 G(N) 所示。最后，在更高的 pH 下，由于桥到环的转变，网络连接性大幅下降，导致最终导致 tau 和 G(N) 突然减少，从而揭示凝胶到溶胶的转变。这些结果可用于根据 pH 响应性微调热响应遥爪聚电解质水凝胶的可注射性。
We report the effect of pH on the dynamics and structure of 3D networks formed by the temperature-dependent hydrophobic association of the end blocks of P(nBuMA(18)-co-TEGMA(15))-b-PDMAEMA(159)-b-P(nBuMA(18)-co-TEGMA(15)) where PDMAEMA and P(TEGMA-co-nBuMA) stand for poly(N,N-dimethylamino ethyl methacrylate) and poly(tri-ethylene glycol methyl ether methacrylate/n-butyl methacrylate respectively) triblock terpolymer in aqueous media. Thanks to the design of the sticky end blocks that can be independently controlled by temperature, it was possible to explore the pH effect, influencing the charge density and chain conformation of the hydrophilic midblock, on the network dynamics and structure by oscillatory rheology and small-angle neutron scattering. Three pH regimes are observed: At low pH ( 6, an appreciable increase of tau (about 6-fold) was observed, likely due to the enhancement of the network connectivity arising from the decrease of the charge density and the increase of the chain flexibility of the poly(2-dimethylamino ethyl methacrylate) (PDMAEMA) block that promote crosslinking, as reflected in G(N). Finally, at even higher pHs, the network connectivity decreases substantially, owing to bridge-to-loop transitions, leading eventually to abrupt decrease of tau and G(N), thus revealing a gel-to-sol transition. These results can be utilized to fine-tune the injectability of the thermoresponsive telechelic polyelectrolyte hydrogels based on their pH responsiveness.