Complex Sequence-Defined Heteropolymers Enable Controlled Film Growth in Layer-By-Layer Assembly.

Area of Science:

• Polymer Chemistry
• Materials Science
• Nanotechnology

Background:

• Layer-by-layer (LbL) assembly is a versatile technique for fabricating thin films.
• Developing advanced polymers for controlled LbL assembly is crucial for data storage applications.
• Digitally-encoded polymers (d-PPDE) offer potential for high-density information storage.

Purpose of the Study:

• To evaluate digitally-encoded poly(phosphodiesters) (d-PPDE) for layer-by-layer (LbL) assembly.
• To investigate methods for controlling film growth and inter-layer distance in d-PPDE based LbL films.
• To assess the suitability of d-PPDE for data storage applications.

Main Methods:

• Synthesis of complex heteropolymers (d-PPDE) with coding units, cleavable spacers, and mass tags.
• Layer-by-layer (LbL) assembly using d-PPDE with poly(allyl amine hydrochloride) (PAH) and poly(sodium 4-styrene sulfonate) (PSS).
• Mass spectrometry (MS) for decoding polymer structures and analyzing film composition.

Main Results:

• d-PPDE with complex primary structures enabled highly controlled LbL film formation, despite sequence heterogeneity.
• Regular LbL growth was observed with alternating d-PPDE and PAH deposition.
• Incorporation of PSS allowed controlled interdistance between d-PPDE layers while maintaining regular LbL growth.
• Low molecular weight d-PPDE also facilitated controlled LbL assembly.

Conclusions:

• Digitally-encoded poly(phosphodiesters) are suitable for controlled LbL assembly.
• The use of intermediate polyanions like PSS offers a strategy to control layer spacing for enhanced data storage.
• d-PPDE presents a promising platform for advanced data storage materials.