Self-Assembly Investigations of Sulfonated Poly(methyl methacrylate-<i>block</i>-styrene) Diblock Copolymer Thin Films

Piñón-Balderrama, Claudia I.; Leyva‐Porras, César; Olayo-Valles, Roberto; Revilla, J.; Schubert, Ulrich S.; Guerrero‐Sánchez, Carlos; Bonilla‐Cruz, José

doi:10.1155/2019/4375838

Cited by 7 publications

(9 citation statements)

References 34 publications

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“…For PA-g-P(t-BA), the peak at 1782.6 is associated with the C==O group. The peaks from 2977.72 to 2825.4 cm -1 represent the weak alkyl C-H stretching [35]. The peaks at 1473.54 and 1384.9 correspond to asymmetric and symmetric C(CH 3 ) stretching, respectively [36,37].…”

Section: Advances In Polymer Technologymentioning

confidence: 99%

Surface Modification of TFC-PA RO Membrane by Grafting Hydrophilic pH Switchable Poly(Acrylic Acid) Brushes

Abbas

Mushtaq

Cheema

et al. 2020

Advances in Polymer Technology

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The grafting of pH-responsive poly(acrylic acid) (PAA) brushes was carried out on the surface of a commercial TFC-PA membrane using surface-initiated atom transfer radical polymerization (SI-ATRP). Poly(t-butyl acrylate) was polymerized through the SI-ATRP method followed by its acid hydrolysis to form PAA hydrophilic polymer brushes. Surface morphology, permeation flux, salt rejection, and pore sizes were investigated. The contact angle for water was reduced from 50° for a pristine membrane to 27° for the modified membrane due to a modification with the hydrophilic functional group and its brush on membrane surfaces. The flux rate also increased noticeably at lower pH values relative to higher pH for the modified membranes, while the flux remains stable in the case of pristine TFC-PA membranes. There is slight transition in the water flux rate that was also observed when going from pH values of 3 to 5. This was attributed to the pH-responsive conformational changes for the grafted PAA brushes. At these pH values, ionization of the COOH group takes place below and above pKa to influence the effective pore dimension of the modified membranes. At a lower pH value, the PAA brushes seem to permit tight structure conformation resulting in larger pore sizes and hence more flux. On the other hand, at higher pH values, PAA brushes appeared to be in extended conformation to induce smaller pore sizes and result in less flux. Further, pH values were observed to not significantly affect the NaCl salt rejection with values observed in between 98.8% and 95% and close to that of the pristine TFC-PA membranes. These experimental results are significant and have immediate implication for advances in polymer technology to design and modify the “switchable membrane surfaces” with controllable charge distribution and surface wettability, as well as regulation of water flux and salt.

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Section: Advances In Polymer Technologymentioning

confidence: 99%

Surface Modification of TFC-PA RO Membrane by Grafting Hydrophilic pH Switchable Poly(Acrylic Acid) Brushes

Abbas

Mushtaq

Cheema

et al. 2020

Advances in Polymer Technology

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“…Fourier transform infrared (FT-IR) spectroscopy (Figure S5) further verified the sulfonation of PS to PSS, as the sulfonated discs exhibit characteristic vibrations at 1015 cm À1 , 1124 cm À1 , and 1147 cm À1 corresponding to S = O, S À O, and O = S = O. [49] The broad signal at around 3386 cm À1 proved the existence of O À H bonds from the sulfonic acid groups (SO 2 OH) and probably water absorption to the hydrophilic PSS side. [50] The colloidal stability of the sulfonated Janus discs in water was confirmed by a zeta potential of À54 mV.…”

Section: Methodsmentioning

confidence: 83%

“…AFM analysis (Figure 3 c and d) revealed a similar disc thickness before and after sulfonation. Fourier transform infrared (FT‐IR) spectroscopy (Figure S5) further verified the sulfonation of PS to PSS, as the sulfonated discs exhibit characteristic vibrations at 1015 cm −1 , 1124 cm −1 , and 1147 cm −1 corresponding to S=O, S−O, and O=S=O [49] . The broad signal at around 3386 cm −1 proved the existence of O−H bonds from the sulfonic acid groups (SO 2 OH) and probably water absorption to the hydrophilic PSS side [50] .…”

Section: Figurementioning

confidence: 86%

Size‐Controlled Formation of Polymer Janus Discs

et al. 2021

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A straightforward method is presented for the preparation of nano‐ to micrometer‐sized Janus discs with controlled shape, size, and aspect ratio. The method relies on cross‐linkable ABC triblock terpolymers and involves first the preparation of prolate ellipsoidal microparticles by combining Shirasu porous glass (SPG) membrane emulsification with evaporation‐induced confinement assembly (EICA). By varying the pore diameter of the SPG membrane, we produce Janus discs with controlled size distributions centered around hundreds of nanometers to several microns. We further transferred the discs to water by mild sulfonation of PS to polystyrene sulfonic acid (PSS) and verified the Janus character by subsequent labelling with cationic nanoparticles. Finally, we show that the sulfonated Janus discs are amphiphilic and can be used as efficient colloidal stabilizers for oil‐in‐water (O/W) emulsions.

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“…Fourier transform infrared (FT‐IR) spectroscopy (Figure S5) further verified the sulfonation of PS to PSS, as the sulfonated discs exhibit characteristic vibrations at 1015 cm −1 , 1124 cm −1 , and 1147 cm −1 corresponding to S=O, S−O, and O=S=O. [49] The broad signal at around 3386 cm −1 proved the existence of O−H bonds from the sulfonic acid groups (SO 2 OH) and probably water absorption to the hydrophilic PSS side. [50] The colloidal stability of the sulfonated Janus discs in water was confirmed by a zeta potential of −54 mV.…”

mentioning

confidence: 84%