Estimation of the Generation and the Weight Fraction of Dense Polymer Regions in Heterogeneous Hydrogels

Abstract

The internal structure of polyacrylamide gels consists of polymer‐dense regions with different densities, which are denoted as “blobs”. The density difference between these blobs decreases when a gel is doped with charged molecules. When a small potential is applied between the ends of such a gel, ionic charge carriers result in a current. A theoretical approach is developed to estimate the weight fraction and the number of blob generation. The current decreases with time as a series of exponentially decreasing terms where the exponent and the multiplier of each term measure the density of the blob and the weight fraction of the corresponding blob generation. magnified image

Tuning the gel size and LCST of N-isopropylacrylamide nanogels by anionic fluoroprobe

“…Thus, as seen in Fig. 1, Py molecules bound to the PNIPAM chains, this indicated that Py should have affected the morphology of nanogel due to its side electrically charged SO − 3 groups [18,19]. Figure 2 shows emission spectra of all samples given in Table 1 at the end of the reactions at 10°C.…”

“…2, the peak is shifted to higher wavelength for more Py containing gels, so it can be said that when the gel contains more Py, it must be smaller-sized gel. The fraction of blobs (polymer-dense regions with different densities) must be higher in the smaller gel [19]. Representative internal morphology of different size nanogels is seen in Fig.…”

“…As known from the literature, Py molecules bind to acrylamide-based polymer chains [17], and they affect the morphology of the gel [18,19] due to the electrically charged side on the Py. Also, in the literature, the introduction of fluorescent molecules can change the hydrophobicity-hydrophilicity balance of the gel particle and so LCST point [20].…”

Synthesis of polyacrylamide hydrogels as p–n‐junction with ionic charge carriers

“…Synthesis was performed at 60°C. These gelation processes are explained in detail in the literature .…”

“…Recently we synthesized p‐ and n ‐type polyacrylamide (PAAm) gels using some doping molecules having counter ions . These ions move through the gel and carry the current under applied voltage when the gel is in swollen state .…”