Tunable multi-stage wettability and adhesion force on polymer brushes triggered by temperature and pH

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  • ReceivedJul 15, 2018
  • AcceptedSep 19, 2018
  • PublishedNov 6, 2018


智能响应性可以将丰富的功能集成到微流体器件中; 同时在刺激前后稳定的润湿区域赋予微流体器件稳定的功能表达. 因此在微流体器件领域, 如何构建具有多重响应的多梯度润湿表面仍然是目前面临的一个巨大挑战. 本文应用原子转移自由基聚合方法在硅基底上制备聚(N-异丙基甲基丙烯酰胺)-b-(N-异丙基丙烯酰胺)-co-2-(甲基丙烯酰氧基)乙基磷酸)聚合物刷. 通过对温度和pH值的控制, 在聚合物表面实现了浸润性的多级梯度变化. 同时, 伴随着温度和pH值的变化, 聚合物刷表面的粘附力也表现为多级梯度变化. 这种多重响应的多级梯度变化的聚合物刷将为多功能微流体和生物分析器件的构建提供一种新方法.

Funded by

the National Natural Science Foundation of China(21774044,21425314,21434009,21421061)


and the Top-Notch Young Talents Program of China.


This work was financially supported by the National Natural Science Foundation of China (21774044, 21425314, 21434009 and 21421061), Ministry of Science and Technology (2013YQ190467), and the Top-Notch Young Talents Program of China.

Interest statement

The authors declare no conflict of interest.

Contributions statement

Zhang S performed the experiments and tested the samples; Wang J did the preliminary ATRP experiments and performed the AFM measurement; Zhang X performed the AFM test with temperature control; Song W conceived the work and wrote the paper. Wang S supervised the work. Zhang S and Wang J gave the equal contribution to the work.

Author information

Shuang zhang received her BSc degree in polymer material and engineering from Changchun University of Technology 2017. Her research interest is the interaction between bio-inspired surface/interface.

Wenlong Song received his BSc degree in applied chemistry in 2002 from Jilin University, China, and awarded his PhD degree in 2007 with Prof. Fengqi Liu and Prof. Lei Jiang under a joint course of the College of Chemistry, Jilin University and the Institute of Chemistry, Chinese Academy of Sciences (ICCAS). Then he worked as a postdoctoral fellow in 3B’s group-Biomaterials, Biodegradables and Biomimetics in Minho University of Portugal. In 2011, he joined the State Key Laboratory of Supramolecular Structure and Materials, Jilin University. His research interest is focused on: (i) investigating the interaction between bioinspired surface/interface and cells; (ii) constructing biomimetic hydrogels for artificial cartilage.


Supplementary information

Experiment section: FTIR of of monomer NIPAM, NIPMAM, MAEP; the wettability of inverse-designed PNIPAM-b-(PNIPMAM-co-PMAEP) brushes following temperature and pH and SEM images of the substrates at pH 12 and 14 are available in the online version of the paper.


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  • Figure 1

    (a) The preparation of the dual-responsive PNIPMAM-b-(PNIPAM-co-PMAEP) brushes by ATRP. (b) The FTIR spectra of PNIPMAM brushes (black line) and PNIPMAM-b-(PNIPAM-co-PMAEP) brushes (red line). (c, d) The thickness of PNIPMAM brushes and PNIPMAM-b-(PNIPAM-co-PMAEP) brushes measured by AFM.

  • Figure 2

    The wettability on PNIPMAM-b-(PNIPAM-co-PMAEP) brushes following temperature rising from 24 to 56°C at pH ~7.0.

  • Figure 3

    The possible conformation change corresponding to each temperature range (a): T<32°C, (b): 32°C<T<44°C, (c): T>44°C. (d) The adhesion force of PNIPMAM-b-(PNIPAM-co-PMAEP) brushes following temperature rising from 24 to 56°C. (d1–d3) Typical adhesion force curve at three temperature set-points of 24, 38 and 50°C, respectively. (e–g) The typical AFM images of PNIPMAM-b-(PNIPAM-co-PMAEP) at 24, 38 and 50°C, respectively.

  • Figure 4

    The wettability on PNIPMAM-b-(PNIPAM-co-PMAEP) brushes following pH change from 1.0 to 12.6.

  • Figure 5

    The dissociation of phosphate groups on PNIPMAM-b-(PNIPAM-co-PMAEP) chains following different pH: (a) pH<3.0; (b) 3.0<pH<12.0; (c) pH>12.0. (d) The relation between adhesion force and pH on PNIPMAM-b-(PNIPAM-co-PMAEP) brushes. (d1–d3) Typical adhesion force curve at three pH setpoints of 1.0, 6.0 and 12.6, respectively. (e–g) Typical AFM images of PNIPMAM-b-(PNIPAM-co-PMAEP) at pH of 1.0, 6.0 and 12.6, respectively.

  • Figure 6

    The multi-stage wettability of PNIPMAM-b-(PNIPAM-co-PMAEP) film following temperature (from 24 to 56°C) and pH (from 1.0 to 12.4). Three-stage wettability change could be observed following both temperature and pH.

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