Formation and dissolution of phase‐separated structures in ultrathin blend films

Ermi, Brett D.; Karim, Alamgir; Douglas, Jack F.

doi:10.1002/(sici)1099-0488(19980115)36:1<191::aid-polb21>3.3.co;2-f

Cited by 34 publications

(89 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the case where each polymer segregates to one of the boundaries (asymmetric segregation) the coexisting phases arrange in a bilayer structure [6,7]. In the case where one component segregates to both interfaces (symmetric segregation) [8][9][10][11], the film morphology depends additionally on the film thickness. Thicker films stay smooth and it was suggested that these films show a trilayer-type structure [9][10][11].…”

mentioning

confidence: 99%

“…In the case where one component segregates to both interfaces (symmetric segregation) [8][9][10][11], the film morphology depends additionally on the film thickness. Thicker films stay smooth and it was suggested that these films show a trilayer-type structure [9][10][11]. For films with a thickness smaller than a characteristic length L c on the order of the interfacial width in bulk, there is the possibility for a phase separation within the film middle layer triggering a surface "roughening" [10,11].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Finite-size effects on surface segregation in polymer blend films above and below the critical point of phase separation

et al. 2004

View full text Add to dashboard Cite

We investigate the influence of temperature and confinement on surface segregation in thin films of deuterated polybutadiene and polyisoprene near the critical point for phase separation. Neutron reflectivity measurements show that polyisoprene enriches at the air and silicon interfaces in both the 1-and 2-phase regions. A transition between in-plane and surface-directed (layered) phase separation is observed with increasing film thickness. Weak critical adsorption effects cause the blend composition profile to be rounded in comparison with profiles normally measured in small liquid mixtures.

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

Finite-size effects on surface segregation in polymer blend films above and below the critical point of phase separation

et al. 2004

View full text Add to dashboard Cite

show abstract

“…It is known that a bicontinuous pattern similar to spinodal decomposition is the characteristics of thin SMA and SMA–H 2 O films [Fig. 2(A) and (B)],3, 4 but the bicontinuous pattern changes into well‐arrayed “holes” in the HSMA film [Fig. 2(C)], and these holes are almost uniform in diameter.…”

Section: Resultsmentioning

confidence: 99%

“…Generally speaking, films of thickness less than 1000 angstroms (Å) are classified as ultrathin films, and of thickness between 1000 and 10000 Å are regarded to as thin films 1. More recently, many studies on surface pattern of spin‐cast thin and ultrathin films are carried out in polymer/polymer blends by using a three‐composition or ternary system: two polymers in a common solvent 2–6. When the thin blend films are annealed at a temperature above T c (critical temperature of polymer blend), a hole or bicontinuous spinodal decomposition surface pattern can be formed.…”

Section: Introductionmentioning

confidence: 99%

“…The formation of these surface patterns is often regarded as a tracking‐phase separation process within these films under the induction of temperature. Ermi et al3 showed that droplets having a higher surface tension than the surrounding medium are expected to cause evaluations in the polymer–air boundary, while droplets of a lower surface tension should lead to depressions in the film surface, resulting in a hole structure. However, the holes in these thin blend films are often irregularly arrayed and not uniform in diameter 2, 3, 7…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hole structure and its formation in thin films of hydrolyzed poly(styrene maleic anhydride) alternating copolymers

Wang

Zhu

Zhang

2000

J. Appl. Polym. Sci.

View full text Add to dashboard Cite

Maleic anhydride moieties on the backbone chains of poly(styrene maleic anhydride) alternating copolymer (SMA) hydrolyzed in a THF solution containing water and hydrochloric acid. Well-arrayed holes were obtained in spin-cast thin hydrolyzed SMA films on a single crystal silicon wafer, and the hole diameter and its distribution were measured with AFM data. Results showed that the hole size was almost uniform, and was influenced by water content when spin speed was kept unchanged. The THF solution with a SMA concentration of about 1 g/mL and weight ratio H 2 O/SMA of 1/3 produced holes having an average diameter of 0.60 m and depth of 206.12 nm, when cast at a spin speed of 1400 rpm. It was noted that the formation of the holes in thin hydrolyzed SMA film was different from the dewetting process in thin homopolymer films, but was associated with the intrinsic properties of the copolymer forming the films. The surfactant effect of hydrolyzed SMA was suggested to interpret the formation of the holes. The holes were described to be the traces of water droplets that were emulsified by the hydrolyzed SMA during casting.

show abstract

Hole‐growth instability in the dewetting of evaporating polymer solution films

Raghavan

Douglas

et al. 2002

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

We investigate the dewetting of aqueous, evaporating polymer [poly(acrylic acid)] solutions cast on glassy hydrophobic (polystyrene) substrates. As in ordinary dewetting, the evaporating films initially break up through the nucleation of holes that perforate the film, but the rapidly growing holes become unstable and form nonequilibrium patterns resembling fingering patterns that arise when injecting air into a liquid between two closely spaced plates (Hele-Shaw patterns). This is natural because the formation of holes in thin films is similar to air injection into a polymer film where the thermodynamic driving force of dewetting is the analogue of the applied pressure in the flow measurement. The patterns formed in the rapidly dewetting and evaporating polymer films become frozen into a stable glassy state after most of the solvent (water) has evaporated, leaving stationary patterns that can be examined by atomic force microscopy and optical microscopy. Similar patterns have been observed in water films evaporating from mica substrates, block copolymer films, and modest hole fingering has also been found in the dewetting of dry polymer films. From these varied observations, we expect this dewetting-induced fingering instability to occur generally when the dewetting rate and film viscosity are sufficiently large.

show abstract

Formation and dissolution of phase‐separated structures in ultrathin blend films

Cited by 34 publications

References 0 publications

Finite-size effects on surface segregation in polymer blend films above and below the critical point of phase separation

Finite-size effects on surface segregation in polymer blend films above and below the critical point of phase separation

Hole structure and its formation in thin films of hydrolyzed poly(styrene maleic anhydride) alternating copolymers

Hole‐growth instability in the dewetting of evaporating polymer solution films

Contact Info

Product

Resources

About