Preparation and Characterization of Poly(N-1H,1H- pentadecafluorooctylmethacrylamide) Langmuir-Blodgett Film

Abstract

ABSTRACT:The monolayer behavior of poly(N-1H,1H-pentadecafluorooctylmethacrylamide (pC7F15MAA) spread on the air-water interface was investigated by measurement of surface pressure-area isotherm at different subphase temperatures. The monolayer of pC7F15MAA was transferred onto solid substrates as Y-type Langmuir-Blodgett (LB) film and the monolayer thickness was calculated by X-Ray diffraction techniques and surface plasmon measurements. Wettability and the surface structure of the LB film were investigated by measuring the static contact angle (cos θ) of water on the surface. The wettability varied slightly with increasing temperature. The critical surface tension measurement suggests that the surface of pC7F15MAA LB film covered mainly with CF 3 groups.KEY WORDS Langmuir-Blodgett Film / Fluorinated Polymer / Surface Plasmon Resonance / Wettability / The Langmuir-Blodgett (LB) technique is an excellent method for preparation of ultrathin films with controlled thickness at a molecular size and well-defined molecular orientation. 1 Recently, polymeric LB films have received much attention due to their superior mechanical and thermal stability than those of low molecular weight LB films 2 and the applications especially in the fields of coatings, optics, and electronics have been discussed. 3,4 The simplest method to fabricate the polymeric LB film is by deposition of preformed polymer monolayers. [5][6][7] For the fabrication of polymeric LB films, comb-like polymers with well-defined hydrophilic groups and hydrophobic hydrocarbon side chains are mostly studied. [8][9][10][11][12][13][14] Monolayer formation and LB film preparation in these polymers are determined by the balance of hydrophilic and hydrophobic interactions.Langmuir-Blodgett films of comb-like polymers with fluorocarbon side chains are attracting much recent attention due to their characteristic properties such as low friction, excellent insulation, excellent durability, and so on. 15,16 The fluorocarbon chains are also hydrophobic and have rigid character (stiffness of the C-F bond), which are suitable factors for stable monolayer formation. However, the deposition of the monolayer on solid substrates is difficult because of the weak interactions among the monolayer due to the low surface energy of fluorinated materials. Nonetheless, a few papers have been reported about monolayers and the fabrication of LB films from comb-like polymers with fluorocarbon side chains. [17][18][19][20][21] In previous works, we have found that polyacrylamide struc- ture is suitable for stable LB film formation due to the self-assembly property based on hydrogen bonding of amide group. 14,22,23 Using this excellent property of the acrylamide backbone, we have demonstrated that poly(N-fluoroalkylacrylamide)s form stable monolayers at the air-water interface and fairly uniform polymer LB films can be easily prepared. 24 In this work, we investigated the spreading behavior of poly(N-1H,1H-pentadecafluorooctylmethacrylamide) (Figure 1) on the water surface to prepare st...

Functional Organized Molecular Assemblies Based on Polymer Nano-sheets

“…[17][18][19][20][21][22] We prepared stable monolayer and LB films fabricated from fluorinated compounds using the excellent property of the N-alkylacrylamide and N-methacrylamide structures. 24,25 This section describes examples of polyfluorinated alkylacrylamide polymers. Polyfluorinated alkyl chains were used instead of long alkyl chains of N-alkylacrylamides.…”

“…This situation was not observed in pC n F 2nþ1 AA nanosheets, but is similar to the contact angle measurement for poly(N-(1H,1H-pentadecafluorooctyl)methacrylamide) (pC7F15MAA) nano-sheets. 25 The p(C7F15MAA/MAc) monolayer (n ¼ 0:34) was deposited on a freshly prepared amino-terminated surface from the hydrophilic side under a surface pressure of 30 mN m À1 with a transfer ratio of unity at 20…”

Surface wettability of amphiphilic fluorinated polymer thin films

“…From space filling model (Corey-Pauling-Kollun (CPK) model) analysis, the full length of pC7F15MAA side chain is calculated as 1.5 nm, assuming that the pC7F15MAA side chains are oriented in vertical direction on the solid substrate. This means that the side chains have a 29°tilting angle from the substrate normal [19]. We determined the water contact angle of a 4-layer pC7F15MAA LB film; the WCA value reached 118° (Fig.…”

Surface Modification of Microchannels with Fluorinated Polymer Langmuir-Blodgett Films

“…1) by conventional radical polymerization [7]. Briefly, N-1H, 1H pentadecafluorooctyl methacrylamide was synthesized with pentafluorooctyl amine (Daikin Co., Ltd, Japan) and methacryloyl chloride according to a reference.…”