Characteristics of thin cellulose ester films spin-coated from acetone and ethyl acetate solutions

Abstract

Spin-coated films of cellulose acetate (CA), cellulose acetate propionate (CAP), cellulose acetate butyrate (CAB) and carboxymethylcellulose acetate butyrate (CMCAB) have been characterized by ellipsometry, atomic force microscopy (AFM) and contact angle measurements. The films were spincoated onto silicon wafers, a polar surface. Mean thickness values were determined by means of ellipsometry and AFM as a function of polymer concentration in solutions prepared either in acetone or in ethyl acetate (EA), both are good solvents for the cellulose esters. The results were discussed in the light of solvent evaporation rate and interaction energy between substrate and solvent. The effects of annealing and type of cellulose ester on film thickness, film morphology, surface roughness and surface wettability were also investigated.

Stability and interface properties of thin cellulose ester films adsorbed from acetone and ethyl acetate solutions

“…Adsorbed layers stemming from acetone solution were thicker than those from ethyl acetate. The same tendency was observed for spin-coated CAP and CAB films when acetone or ethyl acetate was used as solvents [9]. Two factors might explain this behavior: (i) acetone is more volatile than ethyl acetate, leading to thicker films [3][4][5][6][7][8][9] and (ii) the more favorable acid-base interaction for SiO 2 /acetone (+18RT) than for SiO 2 /ethyl acetate (+24RT) [26], so that acetone evaporation is not complete, resulting in thicker polymer films.…”

“…Special attention has been devoted to the effect of solvent used for spin-coating polymer films on the resulting surface properties [3][4][5][6][7][8][9]. Not only the evaporation rate of the solvent plays a very import role on the spin-coated [3][4][5][6][7][8][9] or cast film [10] uniformity, but also solvent quality and the balance between substrate-polymer interaction and substrate-solvent interaction [7][8][9]11]. Nevertheless, there are scarce studies on the effect of solvent on the stability and surface properties of ultrathin (d < 5 nm) adsorbed polymer films.…”

Solution behavior and surface properties of carboxymethylcellulose acetate butyrate

“…PMMA (Walsh and Frances 2003) or trimethylsilyl cellulose (Kontturi et al 2003) films prepared from chloroform were thicker and rougher than those prepared from toluene (less volatile solvent than chloroform). Recently, it was reported (Amim et al 2008) that the thickness and roughness of spin-coated films of a cellulose ester series are strongly influenced by the solvent evaporation rate. However, one must be aware that the interactions balance in the systems formed by substrate, polymer and solvent can not be neglected (Silbeberg 1968;Gesang et al 1996).…”

Effect of humidity and solvent vapor phase on cellulose esters films

“…The effect of relative humidity on the film morphology The morphology of spin-coated polymer films depends on (1) the solvent used for solution preparation (Müller-Buschbaum et al 2001;Strawhecker et al 2001;Petri 2002;Walsh and Franses 2003;Lin et al 2004;Cui et al 2006), (2) the balance between substrate-polymer interaction and substrate-solvent (Silberberg 1968;Petri 2002;Lin et al 2004;Cheung et al 2005;Amim et al 2008;Amim et al 2009) and (3) RH of the atmosphere (Widawski et al 1994;Srinivasarao et al 2001;Bolognesi et al 2005;Park et al 2006;Gliemann et al 2007;Lua et al 2007;Amim et al 2008;Madej et al 2008;Kontturi et al 2009;Liu et al 2009). Regarding the effect of RH, the formation of ''breath figures'' is responsible for the resulting pattern (Widawski et al 1994).…”

“…The structure of polymeric films prepared from polymer solutions depends on the composition, solvent, temperature and air relative humidity (RH) (Widawski et al 1994;Srinivasarao et al 2001;Bolognesi et al 2005;Park et al 2006;Lua et al 2007;Gliemann et al 2007;Amim et al 2008;Madej et al 2008;Liu et al 2009;Kontturi et al 2009). A better understanding of these conditions allows the controlled creation of micro-and nanostructures of cellulose esters films, which are useful for technological applications, such as antireflective coatings or lithographic templates.…”