1 | r""" |
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2 | Calculates the macroscopic scattering intensity for a multi-component |
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3 | homogeneous mixture of polymers using the Random Phase Approximation. |
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4 | This general formalism contains 10 specific cases |
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5 | |
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6 | Case 0: C/D binary mixture of homopolymers |
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7 | |
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8 | Case 1: C-D diblock copolymer |
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9 | |
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10 | Case 2: B/C/D ternary mixture of homopolymers |
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11 | |
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12 | Case 3: C/C-D mixture of a homopolymer B and a diblock copolymer C-D |
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13 | |
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14 | Case 4: B-C-D triblock copolymer |
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15 | |
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16 | Case 5: A/B/C/D quaternary mixture of homopolymers |
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17 | |
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18 | Case 6: A/B/C-D mixture of two homopolymers A/B and a diblock C-D |
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19 | |
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20 | Case 7: A/B-C-D mixture of a homopolymer A and a triblock B-C-D |
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21 | |
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22 | Case 8: A-B/C-D mixture of two diblock copolymers A-B and C-D |
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23 | |
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24 | Case 9: A-B-C-D tetra-block copolymer |
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25 | |
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26 | **NB: these case numbers are different from those in the NIST SANS package!** |
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27 | |
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28 | Only one case can be used at any one time. |
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29 | |
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30 | The RPA (mean field) formalism only applies only when the multicomponent |
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31 | polymer mixture is in the homogeneous mixed-phase region. |
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32 | |
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33 | **Component D is assumed to be the "background" component (ie, all contrasts |
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34 | are calculated with respect to component D).** So the scattering contrast |
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35 | for a C/D blend = [SLD(component C) - SLD(component D)]\ :sup:`2`. |
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36 | |
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37 | Depending on which case is being used, the number of fitting parameters - the |
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38 | segment lengths (ba, bb, etc) and $\chi$ parameters (Kab, Kac, etc) - vary. |
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39 | The *scale* parameter should be held equal to unity. |
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40 | |
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41 | The input parameters are the degrees of polymerization, the volume fractions, |
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42 | the specific volumes, and the neutron scattering length densities for each |
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43 | component. |
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44 | |
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45 | |
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46 | References |
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47 | ---------- |
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48 | |
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49 | A Z Akcasu, R Klein and B Hammouda, *Macromolecules*, 26 (1993) 4136 |
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50 | """ |
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51 | |
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52 | from numpy import inf |
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53 | |
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54 | name = "rpa" |
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55 | title = "Random Phase Approximation - unfinished work in progress" |
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56 | description = """ |
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57 | This formalism applies to multicomponent polymer mixtures in the |
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58 | homogeneous (mixed) phase region only. |
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59 | Case 0: C/D binary mixture of homopolymers |
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60 | Case 1: C-D diblock copolymer |
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61 | Case 2: B/C/D ternary mixture of homopolymers |
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62 | Case 3: B/C-D mixture of homopolymer b and diblock copolymer C-D |
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63 | Case 4: B-C-D triblock copolymer |
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64 | Case 5: A/B/C/D quaternary mixture of homopolymers |
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65 | Case 6: A/B/C-D mixture of two homopolymers A/B and a diblock C-D |
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66 | Case 7: A/B-C-D mixture of a homopolymer A and a triblock B-C-D |
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67 | Case 8: A-B/C-D mixture of two diblock copolymers A-B and C-D |
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68 | Case 9: A-B-C-D four-block copolymer |
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69 | See details in the model function help |
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70 | """ |
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71 | category = "shape-independent" |
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72 | |
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73 | CASES = [ |
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74 | "C+D binary mixture", |
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75 | "C:D diblock copolymer", |
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76 | "B+C+D ternary mixture", |
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77 | "B+C:D binary mixture", |
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78 | "B:C:D triblock copolymer", |
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79 | "A+B+C+D quaternary mixture", |
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80 | "A+B+C:D ternary mixture", |
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81 | "A+B:C:D binary mixture", |
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82 | "A:B+C:D binary mixture", |
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83 | "A:B:C:D quadblock copolymer", |
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84 | ] |
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85 | |
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86 | # ["name", "units", default, [lower, upper], "type","description"], |
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87 | parameters = [ |
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88 | ["case_num", "", 1, [CASES], "", "Component organization"], |
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89 | |
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90 | ["N[4]", "", 1000.0, [1, inf], "", "Degree of polymerization"], |
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91 | ["Phi[4]", "", 0.25, [0, 1], "", "volume fraction"], |
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92 | ["v[4]", "mL/mol", 100.0, [0, inf], "", "specific volume"], |
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93 | ["L[4]", "fm", 10.0, [-inf, inf], "", "scattering length"], |
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94 | ["b[4]", "Ang", 5.0, [0, inf], "", "segment length"], |
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95 | |
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96 | ["K12", "", -0.0004, [-inf, inf], "", "A:B interaction parameter"], |
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97 | ["K13", "", -0.0004, [-inf, inf], "", "A:C interaction parameter"], |
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98 | ["K14", "", -0.0004, [-inf, inf], "", "A:D interaction parameter"], |
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99 | ["K23", "", -0.0004, [-inf, inf], "", "B:C interaction parameter"], |
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100 | ["K24", "", -0.0004, [-inf, inf], "", "B:D interaction parameter"], |
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101 | ["K34", "", -0.0004, [-inf, inf], "", "C:D interaction parameter"], |
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102 | ] |
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103 | |
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104 | |
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105 | source = ["rpa.c"] |
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106 | single = False |
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107 | |
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108 | control = "case_num" |
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109 | HIDE_NONE = set() |
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110 | HIDE_A = set("N1 Phi1 v1 L1 b1 K12 K13 K14".split()) |
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111 | HIDE_AB = set("N2 Phi2 v2 L2 b2 K23 K24".split()).union(HIDE_A) |
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112 | def hidden(case_num): |
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113 | """ |
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114 | Return a list of parameters to hide depending on the multiplicity parameter. |
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115 | """ |
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116 | case_num = int(case_num+0.5) |
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117 | if case_num < 2: |
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118 | return HIDE_AB |
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119 | elif case_num < 5: |
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120 | return HIDE_A |
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121 | else: |
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122 | return HIDE_NONE |
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123 | |
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