Near-ambient pressure X-ray photoelectron spectroscopy for a bioinert polymer film at a water interface

Modification of a Polymer Surface by Partial Swelling Using Nonsolvents

“…11−13 Also, in some cases, a swollen layer is formed just beneath the diffused interface, depending on the type of nonsolvents. 11,15 A similar phenomenon also occurs for other polymers such as acrylate-, 19−21 vinyl ether-, 22−24 ethylene oxide-, 25,26 and oxazoline-based 27,28 polymers in contact with water as a nonsolvent. Consequently, chain dynamics at the nonsolvent interface are well enhanced, 12,19,29−31 drastically affecting the material's functions.…”

“…In these applications, a nonsolvent is used as a liquid. However, the aggregation states and physical properties of polymer chains are generally affected by the sorption of even nonsolvent molecules, especially in the interfacial region. − For example, the outermost surface of a typical glassy polymer, poly­(methyl methacrylate) (PMMA), in contact with nonsolvents such as methanol and water is diffused compared to the air-facing surface because chain segments can be partially dissolved in the liquid phase. − Also, in some cases, a swollen layer is formed just beneath the diffused interface, depending on the type of nonsolvents. , A similar phenomenon also occurs for other polymers such as acrylate-, − vinyl ether-, − ethylene oxide-, , and oxazoline-based , polymers in contact with water as a nonsolvent. Consequently, chain dynamics at the nonsolvent interface are well enhanced, ,,− drastically affecting the material’s functions. − …”

“…An example of the former approach is a plasma-based treatment allowing the surface to be generally hydrophilic. − Energetic ionized species generated from gaseous oxygen attack the polymer surface, where functional groups such as hydroxy, carbonyl, and carboxylic acid groups that contribute to the increase in free energy are generated. The surface segregation of a modifier mixed in a target polymer is also an effective way to alter the surface properties as desired. ,,,,,,, The mechanical processes using injection molding and lamination templates are also known to change the wettability based on morphological effects. While relatively facile and scalable, it is sometimes difficult to apply these methods as they require a condition at a relatively higher temperature to other thermoplastics without damaging the original shape of the materials and devices.…”

“…The surface segregation of a modifier mixed in a target polymer is also an effective way to alter the surface properties as desired. 19,20,22,24,26,28,31,40 The mechanical processes using injection molding 41 and lamination templates 42 are also known to change the wettability based on morphological effects. While relatively facile and scalable, it is sometimes difficult to apply these methods as they require a condition at a relatively higher temperature to other thermoplastics without damaging the original shape of the materials and devices.…”

Water-Induced Crystal Transition and Accelerated Relaxation Process of Polyamide 4 Chains in Microfibers

“…Since the degradation of synthetic polymers in marine environments is based on a hydrolysis reaction, it is crucially important to obtain a better understanding of not only the activities of the specific microorganisms but also the change in the aggregation states and thermal molecular motion of the polymers under aqueous conditions . In general, various polymers have been known to change their aggregation states − and dynamics − even in contact with a non-solvent, leading to a marked change in functions. − Also, it has been reported that the addition of hydrophilic components into polymers to increase the water content promotes the degradation of polymers. − From these perspectives, polyamide 4, hereafter referred to as PA4, which has four carbon atoms between neighboring amide bonds, is considered to be a promising degradable polymer in the family of polyamides. − PA4 can absorb more water molecules due to the higher number density of hydrophilic amide bonds and results in good biodegradability even in normal marine environments. , Furthermore, 2-pyrrolidone, which is the monomer for PA4 upon ring-opening polymerization, can be produced from l -glutamic acid via bioprocesses, and PA4-specific enzymes have also been isolated. , Based on these facts, it is expected that PA4 will be available for use as a fully bio-based degradable polymer in the near future. Nevertheless, many of the detailed studies for aggregation states and physical properties, in aqueous conditions especially, have focused on commercially available PA6 − rather than PA4.…”