This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Supporting Information
Unusual thermogelling behaviour of poly[2‐(dimethylamino)ethyl methacrylate] (PDMAEMA)‐based polymers polymerized in bulk
Jason Yujie Zhenga, Mein Jin Tanb, Praveen Thoniyotb and Xian Jun Loha,b,*
(a) Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576, Singapore.
(b) Institute of Materials Research and Engineering (IMRE), 3 Research Link, Singapore 117602, Singapore.
wt %) were heated at 1.2 °C min‐1 while both the transmittance at wavelength, 600 nm (1 cm path length) and
the solution temperature were monitored.
5. Rheological studies
Steady and dynamic rheological experiments were performed on a Discovery HR‐3 hybrid rheometer (TA
Instruments). The sol‐to‐gel transition of the polymer aqueous solution was investigated by dynamic
rheometry. The aqueous polymer solution was placed between parallel plate of 20 mm diameter and the steel
Peltier plate at a gap of 800 m. The data were collected under a controlled strain of 1% (8 x 10‐4 rad) and a
frequency of 1 Hz (6.283 rad s‐1). The heating rate was 1 °C min‐1. Dynamic frequency spectra were obtained in
the linear viscoelastic regime (LVR) of each sample, as determined by strain amplitude sweep experiments.
0
0.01
0.02
0.03
0.04
0.05
0.06
25 30 35 40 45
Chan
ge in
peak width (Δω
1/2)
Temperature (°C)
Fig. S3 Rheological profile of copolymer, DM4 (10 wt %) aqueous solution as a function of temperature.
6. Transmission Electron Microscopy (TEM)
The samples were imaged on a JEOL JEM‐2010F FasTEM field emission transmission electron microscope
operated at 100 kV. Samples were prepared for TEM by directly depositing one drop of sample solution (10 mg
mL‐1) containing 0.1 wt % phosphotungstic acid (PTA) onto copper grids, which were coated in advance with
supportive Formvar films and carbon (Agar Scientific). The samples were kept in an oven for 12 h for drying at
25 °C before TEM imaging.
References
1. V. P. Nam Nguyen, N. Kuo and X. J. Loh, Soft Matter, 2011, 7, 2150‐2159. 2. X. J. Loh, Z.‐X. Zhang, Y.‐L. Wu, T. S. Lee and J. Li, Macromolecules, 2009, 42, 194‐202. 3. B. Jeong, Y. H. Bae and S. W. Kim, Macromolecules, 1999, 32, 7064‐7069. 4. B. Jeong, Y. Han Bae and S. Wan Kim, Colloids and Surfaces B: Biointerfaces, 1999, 16, 185‐193. 5. B. Jeong, C. F. Windisch, M. J. Park, Y. S. Sohn, A. Gutowska and K. Char, The Journal of Physical
Chemistry B, 2003, 107, 10032‐10039. 6. B. H. Lee, Y. M. Lee, Y. S. Sohn and S.‐C. Song, Macromolecules, 2002, 35, 3876‐3879. 7. X. J. Loh, S. H. Goh and J. Li, Biomacromolecules, 2006, 8, 585‐593. 8. A. Durand, D. Hourdet and F. Lafuma, The Journal of Physical Chemistry B, 2000, 104, 9371‐9377. 9. X. J. Loh, Journal of Applied Polymer Science, 2013, 127, 992‐1000. 10. X. J. Loh, S. H. Goh and J. Li, The Journal of Physical Chemistry B, 2009, 113, 11822‐11830. 11. J.‐h. Ma, C. Guo, Y.‐l. Tang and H.‐z. Liu, Langmuir, 2007, 23, 9596‐9605.