Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize the pDEAEA following a published procedure (Figure  1, step 3) [18, 23]. The resulting polymer had a molecular weight of 4,380 g/mol as determined by GPC. This polymer was deposited on the external surface of the pSi rugate

filter by spin coating (Figure  1, step 4), in a manner that the polymer acts as a barrier to prevent the ingress of water into the porous matrix.In order to test the reliability of using the optical properties of pSi rugate filters and the penetration of the polymer inside https://www.selleckchem.com/products/Ispinesib-mesilate(SB-715992).html the pores, the white-light reflectance SAR302503 cell line spectrum from the pDEAEA-covered pSi

film modified with silane was recorded and compared with the silane-functionalized pSi film without polymer. The spectrum obtained from the silanized pSi displays a sharp resonance at a wavelength of 540.0 nm (Figure  2a, trace A). Figure  2a (trace B) shows the reflectance spectrum at the same spot after spin coating of the polymer. The rugate peak is observed at a wavelength of 541.8 nm, very similar to the resonance observed for the control, therefore confirming that the polymer has not penetrated into the pores to a significant extent. The intensity of the reflectance spectrum of the sample high throughput screening modified with pDEAEA is slightly smaller (~1.3 times smaller) than the one observed for the control. Had the pores been filled with polymer during spin coating, the resonance peak would be expected to red shift by approximately 111 nm according to a simulation using the transfer matrix method. We conclude from these observations that the presence of the second pDEAEA does not obstruct the optical spectrum of the pSi reflector. In addition, the lack of

a significant change in the wavelength of the rugate peak before and after the polymer layer deposition confirms that pDEAEA does not infiltrate the porous layer. Figure 1 Fabrication of pSi-pDEAEA composite films. A piece of flat silicon is subjected to electrochemical etching using HF as an electrolyte followed by (1) thermal oxidation, (2) the oxidized pSi film is functionalized with the silane, (3) the DEAEA monomer is subjected to RAFT polymerization reaction, and (4) the pDEAEA is spin-coated onto the surface. Figure 2 Reflectance spectra of the oxidized pSi surface and FTIR-ATR spectra for pSi samples. (a) Reflectance spectra of the oxidized pSi surface modified with silane (A) and of the pSi after spin coating of pDEAEA (B). (b) FTIR-ATR spectra for pSi samples modified with silane (A) and with a layer of pDEAEA spin-coated on the surface (B). The spectra were baseline-corrected.