Tunable Thin Film Periodicities by Controlling the Orientation of Cylindrical Domains in Side Chain Liquid Crystalline Block Copolymers

Table 1

Characterization data of the synthesized BCPs.

BCP	Label^a	Mn^b (kg Mol^–1)	Đ	wPS^c	fPS^c	dspacing^d (nm)	LC periodicity^e (nm)	Morphology^f
PS-b-PGMA	SG4	3.9	1.23	0.73	0.68	8.9	—	Disorder
PS-b-P1FMA	S1F	5.2	1.25	0.60	0.67	9.6	—	LAM
PS-b-P4FMA	S4F	6.4	1.21	0.48	0.56	12.1	(2.6)	LAM
PS-b-P6FMA	S6F	6.6	1.19	0.42	0.54	11.6	3.2	HEX
PS-b-P8FMA	S8F	7.5	1.18	0.38	0.50	11.5	3.6	Asym HEX

^aThe labels SG and S(X)F refer to PS-b-PGMA and PS-b-PXFMA, respectively, while the number to the right refers to the number-average molecular weight (M_n) of the polymer. ^bM_n and dispersities (Đ) were obtained by SEC using THF as the eluent based on PS standards. ^cPS weight fractions (w_PS) of PS-b-PGMA were calculated via ¹H NMR and PS weight (w_PS) and volume fractions (f_PS) of PS-b-PXFMA were further estimated based on 100% introduction rate of side chain using bulk densities for each block (1.05 g cm⁻³ for PS, 0.805 g cm⁻³ for PGMA, 1.43 g cm⁻³ for P1FMA, 1.45 g cm⁻³ for P4FMA, 1.66 g cm⁻³ for P6FMA and 1.73 g cm⁻³ for P8FMA). ^dThe domain spacings (d-spacing) were estimated from the position of first-order scattering peak in the SAXS profile upon thermal annealing at 150°C for 24 h. ^eThe periodicity of LC side chain was determined by the position of first-order scattering peak in the WAXD profile of homopolymer upon thermal annealing at 150°C for 24 h. ^fThe bulk morphologies were determined by SAXS and TEM.