Nanomechanical characterization and modeling of anodized porous aluminum oxide thin films with photografted anti-biofouling polymer brushes on their pore walls

Abstract

Nanocomposites are known for their unique properties with many potential applications. In the present work, porous anodic aluminum oxide (AAO) thin films were processed on glass substrates and subsequently photo-grafted with a zwitterionic anti-biofouling polymer. This allows to fabricate scratch-resistant, transparent anti-biofouling films. The microstructure and how it is affected by nanomechanical testing are investigated by scanning electron microscopy and atomic force microscopy. It is shown that the polymer forms a thin layer on the pore walls and in deionized water, the pore diameter changes due to swelling of the polymer. The nanomechanical and scratch resistance properties are studied using a nanoindenter testing system. The experimental results are validated via numerical calculations. The values of the elastic modulus and hardness are shown to be in good agreement with the numerical ones, and under dry conditions, higher values were obtained in comparison to wet films. There is also a large agreement between modeling and microscopic deformation behavior of the films. Finally, the critical loads in dry and wet conditions for the non-coated AAO samples are approximately the same, while for the coated samples, the critical load is reached rapidly in wet condition in comparison to the dry one.

Cytocompatible, soft and thick brush-modified scaffolds with prolonged antibacterial effect to mitigate wound infections

“…Moreover, hardness and reduced modulus were both found to decline with progress of polymerization, indicating the formation of softer brushes caused by longer flexible chains. 46,74 Generally, short polymer brushes are stiff and provide great resistance to the indenter (elastic and plastic deformation) as it pushes down on them, resulting in higher H and E r 75 (Fig. 3a and Fig.…”

A Bacteria and Cell Repellent Zwitterionic Polymer Coating on Titanium Base Substrates towards Smart Implant Devices

“…Among such processes, photopolymerization has only received limited interest, despite the fact that it is a relatively simple coating method, commonly implying often short processing times and only requiring a few precursors, e.g., a monomer, initiator, and appropriate solvent [19,57]. As outlined above (see the experimental section), a simple photopolymerization process was developed in this work for the coating of titanium substrates with polySBMA, but this process can be extended to other substrates [19,20]. SBMA was polymerized into a bio-, and hemocompatible polysulfobetaine in the presence of PPD, an initiator substance of certified food grade quality, with water as solvent, in order to minimize cytotoxicity and environmental impacts.…”

“…The sheets were cut into 0.75 × 1 cm 2 samples, degreased in 9.9% ethanol in an ultrasonic bath, rinsed twice with ethanol, and then dried with compressed air. These substrates were then treated with oxygen plasma (300 W; 0.2 mbar O 2 pressure; Plasma Technology, Herrenberg Gültstein, Germany) for 5 min and 30 s. Subsequent to this activation treatment, the substrates were immediately primed with TMSPMA using a chemical vapor deposition process as described in previous articles [19,20]. Coating onto the primed substrate surfaces with polySBMA was conducted using a photopolymerization process.…”

“…Zwitterionic polymer films appear to be among the most promising strategies as they fulfill the required functionality with simultaneous proven biocompatibility [3]. In recent works [19,20], it has been shown that polySBMA (poly(sulfobetaine methacrylate)) can be successfully grafted from/onto the pore walls of porous aluminum and titanium oxide films (obtained via anodization of the metal) using a versatile and environmentally friendly photografting method. The polySBMA films were shown to wet the pore walls, leading to the creation of a 3D nanocomposite that was mechanically resistant and particularly effective at repelling proteins and bacteria.…”

Porous but Mechanically Robust All-Inorganic Antireflective Coatings Synthesized using Polymers of Intrinsic Microporosity

“…The maximum load is detected by the instrument using acoustic emission feedback picked by a piezoelectric detector arranged next to the indenter. The maximum reached load was 13 mN with a scratch depth of about 130 nm (Figure 6d), which is much higher than that of the porous anodic aluminum oxide (AAO) ARC structures in which the indenter can penetrate down to 350 nm at 2 mN load, 57 and approximately two times better than we achieved for optical coatings on commercial lenses tested using the same testing parameters. (Figure S6, Supporting Information).…”