Supporting Information

Transcription

1 Supporting Information Hydration-Induced Phae Tranition in Surfactant and Lipid Film Sebatian Björklund* and Vitaly Kocherbitov Department of Biomedical Science, Faculty of Health and Society and Biofilm Reearch Center for Biointerface, Malmö Univerity, Malmö, Sweden * Page S2 Page S3 Page S4 Page S5 Page S6 Page S7 Table of content Figure S1 Figure S2 Figure S3 Figure S4 Figure S5 Supporting Text S1

2 (A) 8 Mean film thickne (nm) (B) 8 Mean film thickne (nm) Concentration DDAO in water (wt%) 4 wt% DDAO 1 wt% DDAO 2 wt% DDAO Number of 2µl application Figure S1. (A) Mean thickne of DDAO film a a function of concentration ued for pincoating. (B) Number of 2 µl application for different DDAO concentration ued for pincoating. In all cae 2 µl of the aqueou DDAO olution wa topically applied to the pinning enor between 1-5 time. No ignificant difference in thickne wa oberved between film that were prepared with different number of application. The reaon for thi may be related to charge repulion of the firt applied layer and conecutive application, which would act to minimize build-up of the film thickne after the firt application. The relative tandard deviation of the mean thickne were between 7-13 % (n = 3-7) for the film prepared with 4, 1, and 2 wt% DDAO in water. It can be noted that the mean thickne of the film prepared with 1 wt% DDAO wa merely 11 nm and in thi cae the tranition between the olid and ellar phae wa detected, while the phae tranition at higher water activitie were not detected. With repect to the two group of data, howing either monohydrate formation or a direct tranition into the ellar phae, it can be noted that of all DDAO experiment (n=14), 3 howed the equilibrium tranition (olid-monohydrate and monohydrate-ellar), while the ret howed the metatable tranition (olid-ellar). The thickne of the film that formed monohydrate were 168, 182, 71 nm, while the correponding thicknee for the film not howing thi tranition were 46, 46, 49, 49, 53, 53, 54, 24, 37, 543, 65. Thi indicate that the thinner film are le likely to form MH, while thicker film may or may not form MH. Taken together, the oberved polymorphim cannot concluively be related to the film thickne. S2

3 n= (A) OG (C) MO (B) OG (D) MO (E) DTAC int hex 3 3 xh D/n (1 6 ) hex (H) CTAC hex 5 1 xh mh lc 5 lc xh mh (G) CTAC (F) DTAC int hex xh 1 (I) SDS 1 (J) SDS Time (h) Time (h) Figure S2. f n (left panel) and D n (right panel) a a function of time for 3D urfactant film under the influence of continuou hydration. Abrupt change of f n and D n indicate hydration-induced phae tranition. Film thicknee are: OG (A and B) - 19 nm, MO (C and D) nm, DTAC (E and F) nm, CTAC (G and H) nm, SDS (I and J) nm. Abbreviation: olid, hh olid hemihydrate, mh olid monohydrate, ellar, ic, int intermediate, hex hexagonal, lc liquid crytalline or gel phae, ellar. All data are preented with the dry film a reference tate. 5 S3

4 (A) Figure S3. f n (A) and D n (B) a function of for a19 nm thick OG film. Cloe-up of the high water activity region. Around ~.92 f n change due to a tranition from ellar to ic phae, while the change jut below ~.96 can be explained by a tranition from the ic phae to an iotropic ellar phae. The ellar phae, cloe to the phae boundary (to the ic phae) i imilar to the ic phae, which may explain the complicated change of f n (A) and D n oberved above ~.96. All data are preented with the dry film a reference tate. (B) D/n (1 6 ) S4

5 (A) 1 5 a (B) 5 a (C) (D) D/n (1 6 ) a D/n (1 6 ) a Figure S4. f n a a function of for a19 nm thick OG film. (A and B) Illutration of how the overtone dependence change from poitive to negative behavior due to change of the vicoelatic propertie of the film. In (A) the dry film i ued a reference, which mean that the frequency hift f n are the ame for the different overtone n initially (a expected from the Sauerbrey equation). However, if it i aumed that the change of f n around ~.2 i due to a tranition from an amorphou tate ( a ) into a more crytalline/ordered olid tate () it i reaonable to normalize f n with the value correponding to thi olid tate according to the Sauerbrey equation (i.e. in B the region between ~.3-.6 i defined o that f! n! ). In thi cae it i clear that the overtone dependence follow f n n! below ~.3 and f n n!!/! above ~.6. Thi i in line with the diipation data in (C) howing that the decay time of the quartz crytal ocillation decreae, leading to a decreaed diipation with repect to the dry coated enor, around ~.2. For the ake of clarity, (D) how D n data normalized with the value between ~ S5

6 β Figure S5. Exponent β a a function of water activity for a 24 nm thick DDAO film (correponding to the data hown in Figure 5 A in the main article). The reult demontrate that the hydration-induced phae tranition from olid to the liquid crytalline ellar phae change the order of overtone from Sauerbrey condition ( f n n! ) to liquidlike behavior (i.e. negative dependence imilar to f n n!!! ). See Supporting Text for additional information. S6

7 Supporting Text The dependence of the exponent n with repect to water content wa evaluated a explained in detail below. The vicoelatic film in air i decribed by the following relation: f! = 2f!! m! 1 + Z!! m!! π! n! Z! 3Z!! m! (S1) Eq. S1 can be rewritten a: f! = a + bn!, (S2) where a = 2f!! m! Z! and b = 2f!! m!! Z!! π! (3Z! Z!! m!! ). The behavior of a emi-infinite liquid can be decribed a: f! = bn!!/! (S3) Finally, frequencie for rigid film do not how any dependence on the overtone number: f! = bn! (S4) Or alternatively: f! = a (S5) In general, the coefficient a and b are dependent on rheological propertie and the ample ma. Eq. S2-S5 can be generalized a follow: f! = a + bn!, (S6) where β can take value of 2, -1/2 and. Unfortunately, plotting the frequency-overtone number dependence in log-log coordinate will not reolve the β value due to the um (a + bn! ) preent on the right-hand ide in eq. S6. Intead, the coefficient of eq. S6 can be found uing numerical method. We performed uch calculation for DDAO (ee Fig. S5) uing a multidimenional uncontrained nonlinear minimization method (included in MATLAB oftware package). The reult in Fig S5 how a clear tranition from the Sauerbrey regime (β ) to a liquidlike regime (β -.5). One hould note that the three theoretical model are only limiting cae; their condition are not exactly met in experiment. Indeed, in reality, the liquid film are not emi-infinite, while the olid and vicoelatic film can have a ignificant roughne that can have an impact on overtone behavior. S7