Structure and Stability of Two-Component Langmuir−Blodgett Multilayers Containing Cadmium Arachidate and Polyglutamate Determined by Reflectivity

Abstract

Interlayer diffusion and interdigitation in Langmuir−Blodgett multilayers containing asymmetric interfaces between cadmium arachidate (CdA) and an octadecyl-substituted polyglutamate (PG) were studied using neutron reflectometry and X-ray reflectometry. It was found that the structure of the two-component CdA/PG multilayers is less stable to annealing than is the structure of multilayers containing only CdA or only PG. The PG side chains and CdA tails at adjoining layers appear to interdigitate significantly in unannealed multilayers, and this interdigitation becomes more marked after annealing.

Stability and Disturbance of Fatty Acid Layers by Polymer in Lead Stearate/Poly(tert-Butyl Methacrylate) Alternating Langmuir—Blodgett Films

“…It is noteworthy that the stability of the alternating LB lm with polymer decreased greatly on annealing, which shows that the PtBMA layer does not function as a barrier to interlayer m ixing on annealing, as was reported by Shimomura et al 1 In the meantime, the structure of the CdA/PG multilayers reported by Vierheller et al was unstable in the unannealed state. 3 However, the present study shows the unannealed LB lm with PtBMA to have a more stable structure than the corresponding annealed lm. Thus, PtBMA layers in the alternating LB lm play two roles: they stabilize the structure before annealing and disturb the structure after annealing.…”

“…Recently, phenomena such as interlayer mixing, ablation, and interdigitation at the interfaces in alternating Langmuir-Blodgett (LB) lms have been intensively studied. [1][2][3][4] All of these phenomena serve to destroy the structure of multilayered LB lms. The construction of a stable LB lm has therefore drawn intensive attention.…”

“…Enormous effort has been exerted to elucidate the structure of LB lms using X-ray, FT-IR , and Raman spectroscopy, as well as ellipsometry. [1][2][3][4][5][6][7][8] Shimomura et al observed that the exposure of layered structures to elevated temperatures could increase the m olecular mobility such that the molecules diffused into adjacent layers. 1 They determined the interlayer diffusion (interlayer mixing) from the splitting of the CH 2 or CD 2 scissoring band in the FT-IR spectrum.…”

“…Vierheller et al also found that in LB multilayers containing asymmetric interfaces between cadmium arachidate (CdA) and an octadecyl-substituted polyglutamate (PG), the structure of the twocomponent CdA/PG multilayers is less stable to annealing than the structure of m ultilayers containing only CdA or PG. 3 They attributed this phenomenon to interdigitation between PG side chains and CdA tails in adjoining layers. The interdigitation was signi cant in unannealed multilayers and became m ore m arked after annealing.…”

Self-Assembly of Substituted Polyglutamates on Solid Substrates: The Side-Chain Effect

“…Our understanding of self-assembly of substituted polyglutamates on the charged mica surface is based (i) on the results of studies of intermolecular interactions in polypeptide solutions, which are driven by dipole−dipole interactions between polymer backbones, (ii) on the tendency of the side groups in polyglutamates to crystallize when the number of carbon atoms in the substituent increases, − ,,, ,,, and (iii) on the results obtained in the current work. The following scheme of the polymer−surface and polymer−polymer interactions can be proposed, as shown in Figure .…”